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P0C17 and P0C18 Tahoe Hybrid 2008
Hello. I have Tahoe Hybrid 2008 car not started.We install new 12v battery but car still not started.
I have 2 trouble code: P0C17 Drive motor A position sensor not learned P0C18 Drive motor B position sensor not learned Any body help me please. Thanks |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Check the voltage of the hybrid high voltage battery through a scan tool (or if you know what you are doing and observe high voltage safety precautions, check at the high voltage battery terminals). If the voltage is less than 192V, the computer will not be able to learn the drive motor positions. This could also be why your Tahoe is not starting. Dead hybrid battery. If your battery is too low, you may not need a new one. You just need to find a hybrid tech who can "grid charge" the whole pack at once.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
So big C what is the background on the vehicle? Has it been setting un-driven for a long period of time?
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Jaime
(Post 267402)
Check the voltage of the hybrid high voltage battery through a scan tool (or if you know what you are doing and observe high voltage safety precautions, check at the high voltage battery terminals). If the voltage is less than 192V, the computer will not be able to learn the drive motor positions. This could also be why your Tahoe is not starting. Dead hybrid battery. If your battery is too low, you may not need a new one. You just need to find a hybrid tech who can "grid charge" the whole pack at once.
but for that I need GM tech 2 scanner tool. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Chicago38
(Post 267426)
I found an official document GM where it is indicated how to charge the battery.Jump assist mode.
but for that I need GM tech 2 scanner tool. https://www.greenhybrid.com/forums/f...results-31736/ |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Jaime
(Post 267427)
I recently purchased one of these VCXNano scantools that comes with a Windows version of a Tech2. This may let you initiate the Jump Assist mode. I would first verify that the battery really is discharged by reading the module voltages. If you already have an OBD2 scanner, look at the following post that shows you how to read the voltages:
https://www.greenhybrid.com/forums/f...results-31736/ they tried to clear trouble code and reprogram the sensor, but it didn't work out. They tried 12 times. The last thing they can do is change the whole transmission. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
That is an expensive transmission. $6,000.00 might not be much money to you but ole dnt1010 says woah hold up here a minute LOL. If this were mine I would want to get another opinion, even if I had to have it towed to a hybrid specialty shop. When I see these dealership diagnosis I am always reminded of the time I had bought a new ford truck and the cruise control stopped working. Took it in and they said it was a bad control module and they would have to order it and would be weeks before it came in. When i got home I crawled underneath the truck just to look it over a bit and found that my New Puppy Dog had chewed the wiring harness. Wired it back up with some wiring connectors and shrink tape and drove it for years no problems. Moral of the story is sometimes these guys just simply overlook what should be be obvious.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by dnt1010
(Post 267440)
That is an expensive transmission. $6,000.00 might not be much money to you but ole dnt1010 says woah hold up here a minute LOL. If this were mine I would want to get another opinion, even if I had to have it towed to a hybrid specialty shop. When I see these dealership diagnosis I am always reminded of the time I had bought a new ford truck and the cruise control stopped working. Took it in and they said it was a bad control module and they would have to order it and would be weeks before it came in. When i got home I crawled underneath the truck just to look it over a bit and found that my New Puppy Dog had chewed the wiring harness. Wired it back up with some wiring connectors and shrink tape and drove it for years no problems. Moral of the story is sometimes these guys just simply overlook what should be be obvious.
Sorry for my english this is not my born language:-) |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Do you think my problem may be related to poor contact or cable harness in the transmission?
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Chicago38
(Post 267470)
Do you think my problem may be related to poor contact or cable harness in the transmission?
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by SonomaGTLS6
(Post 267471)
Might be worth reseating all of the connectors. Strange to me that both position sensors would fail at the same time. If you can find pinouts for the connectors on the trans that might be a start for troubleshooting...make sure proper voltage is at the pins necessary. If they are sensor pins going back to the PCM or TCM, I’d assume they are fed by a 12V line. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Chicago38
(Post 267472)
I'm not sure that I understood everything correctly. But I checked all the fuses and relays. I also put a new 12v battery.
Another thing you could do is check out the pins in the connector shown on page 5/6 here...looks like there’s some service info highlighting that terminals could be out of place. Maybe someone with access to inline connector or harness schematics for service information can get the pinouts for the trans connectors. https://ww2-secure.justanswer.com/up...7_222501_1.pdf |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Jaime
(Post 267427)
I recently purchased one of these VCXNano scantools that comes with a Windows version of a Tech2. This may let you initiate the Jump Assist mode. I would first verify that the battery really is discharged by reading the module voltages. If you already have an OBD2 scanner, look at the following post that shows you how to read the voltages:
https://www.greenhybrid.com/forums/f...results-31736/ I also disconnected the connectors on the transmission trying to find bad contacts, but everything is in ok. I do not even know it makes sense to remove the transmission pan and check the wiring harness inside?! |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
A hybrid battery at 213V is completely dead. There are 240 cells. For a prismatic module to drop below 1V/cell, it's pretty much a death sentence. When the battery is EMPTY, but can still properly hold a charge, you will NOT see a voltage less than 288V. A battery with some usable charge that has sat for a year will still read greater than 296V.
I can only conclude the vehicle sat for so long, the already tired HV battery completely discharged. There is NO way to reliably diagnose the vehicle with the HV battery in that state. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Still not sure of the background of the vehicle? Regardless of that, if your battery voltage check is correct then the source of your problem is most likely a completely dead Hybrid battery pack, not the $6,000.00 transmission. That is actually good news as a replacement battery is much cheaper than a transmission. If you are in the Chicago area you might give Mike a call over at Best Hybrid Batteries just outside of Chicago (800) 770-8832 . I recently bought a new hybrid battery from them and so far it is doing OK. I currently have the old hybrid battery pack on my workbench doing some testing while waiting to see how the new one performs over the next few weeks. The old battery appears to be badly deteriorated from my preliminary test results. Hoping to be complete all the data gathering by the end of this weekend. It takes about 3 hours per module to test so 3 x 40 modules equals 120 man hours. My time is worth around $400.00 per hour so I will have around a $48,000.00 investment when done LOL (enough to buy 12 brand new batteries, or actually a entire new car) No problem though as I am happy to donate my time to contribute to the GreenHybrid forum knowledge base. Success is dictated by the ability to do better than good enough.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Purchase:
LPC-100-350 APC-35-350 400V+ 1A diode/rectifier Install the diode in the (+) output lead of the LPC-100-350 Wire the LPC input to a suitable AC cord. Remove the safety plug. Open the battery. Attach the DC out leads of the LPC-100-350 to the relays on the battery side. Energize the LPC Install the safety plug. Charge until pack is at or near 286V Remove the safety plug De-energize the LPC remove the (-) lead from the relay. Wire the APC-35-350 output in series with the LPC, (-) to relay, (+) to (-) of LPC. Wire their inputs in parallel. Energize both supplies. Install safety plug Charge for the sooner of 6 hours or until the pack has warmed to the touch. Remove safety plug De-energize power supplies Detach power supplies from battery. Close battery Install safety plug Disconnect 12V for 2 minutes Reconnect 12V Profit |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by S Keith
(Post 267557)
Purchase:
LPC-100-350 APC-35-350 400V+ 1A diode/rectifier Install the diode in the (+) output lead of the LPC-100-350 Wire the LPC input to a suitable AC cord. Remove the safety plug. Open the battery. Attach the DC out leads of the LPC-100-350 to the relays on the battery side. Energize the LPC Install the safety plug. Charge until pack is at or near 286V Remove the safety plug De-energize the LPC remove the (-) lead from the relay. Wire the APC-35-350 output in series with the LPC, (-) to relay, (+) to (-) of LPC. Wire their inputs in parallel. Energize both supplies. Install safety plug Charge for the sooner of 6 hours or until the pack has warmed to the touch. Remove safety plug De-energize power supplies Detach power supplies from battery. Close battery Install safety plug Disconnect 12V for 2 minutes Reconnect 12V Profit |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
No. According to this, jump assist won't work if the hybrid battery is less than 240V:
https://f01.justanswer.com/Bluegoril...ocument-10.pdf The likelihood of your battery being salvageable is essentially zero, but it's probably worth $50 worth of power supplies and 8 hours (2 hr install, 6 hr charge) of your time to find out. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Jaime
(Post 267559)
Same purpose. To charge the battery. The Jump Assist mode is not recommended to be done for more than 30 minutes, but with S Keith's instructions you can fully charge the battery.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
In the instructions for jump assist there are mentions of high voltage contactor relays, you need to compare two battery readings and if the difference is more than 30 volts, it means that high voltage contactor ralays is not closed. Who can say something about this relay?
Because it shows completely different values when I check. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
There are 2 HV contact relays inside the battery. They are open any time the car is not ready. When power-on diagnostics and sync has been completed, the two relays are closed, and the battery is connected to the HV system. If the battery fails initial check, or is low voltage, the HV relays will not close, and the battery will remain isolated from the car.
In some cases, one relay will energize, while the other will not. Regardless of any issue with the relay(s), a battery voltage of 213V is the first problem. It is dead, and it is below the 240V threshold for Jump Assist to work. Neither relay affects the BATTERY voltage reading as the reading is taken from the sensing harness, not the main leads. You're grasping at straws. HV battery is DEAD. Jump Assist will not function because battery is < 240V. You're going to have to open the HV battery to diagnose. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by S Keith
(Post 267628)
There are 2 HV contact relays inside the battery. They are open any time the car is not ready. When power-on diagnostics and sync has been completed, the two relays are closed, and the battery is connected to the HV system. If the battery fails initial check, or is low voltage, the HV relays will not close, and the battery will remain isolated from the car.
In some cases, one relay will energize, while the other will not. Regardless of any issue with the relay(s), a battery voltage of 213V is the first problem. It is dead, and it is below the 240V threshold for Jump Assist to work. Neither relay affects the BATTERY voltage reading as the reading is taken from the sensing harness, not the main leads. You're grasping at straws. HV battery is DEAD. Jump Assist will not function because battery is < 240V. You're going to have to open the HV battery to diagnose. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
First, 7.7V cells mean nothing. As you can see from data provided in other threads, modules with good voltage can have crap capacity.
There is ONE supplier on ebay that I trust: https://www.ebay.com/usr/tedb8?_trks...72.m2749.l2754 He sells them for about $55 each and gives a one year warranty. I've purchased them and tested them, and they were excellent. Everything else is a crap shoot. Alternatively, you can do what Jamie did - purchase 2X Prius C batteries (cool climate and < 60K miles) and use those to build. BEFORE YOU DO ANYTHING LIKE THOSE OPTIONS, YOU NEED TO OPEN THE BATTERY AND CONFIRM THAT YOU HAVE AN ACTUAL BATTERY ISSUE. All data thus far points that direction, but you need to be certain. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by S Keith
(Post 267631)
First, 7.7V cells mean nothing. As you can see from data provided in other threads, modules with good voltage can have crap capacity.
There is ONE supplier on ebay that I trust: https://www.ebay.com/usr/tedb8?_trks...72.m2749.l2754 He sells them for about $55 each and gives a one year warranty. I've purchased them and tested them, and they were excellent. Everything else is a crap shoot. Alternatively, you can do what Jamie did - purchase 2X Prius C batteries (cool climate and < 60K miles) and use those to build. BEFORE YOU DO ANYTHING LIKE THOSE OPTIONS, YOU NEED TO OPEN THE BATTERY AND CONFIRM THAT YOU HAVE AN ACTUAL BATTERY ISSUE. All data thus far points that direction, but you need to be certain. So one cell 5.05v double 10,1v |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Terminology:
block = 20 voltages the car monitors comprised of 2 modules module = 6 cell battery, 40 per HV battery pack cell = single 1.2V NiMH cell, 6 per module, 240 per HV battery pack If you're able to monitor block voltages with the diagnostic tool, and all 20 blocks are between 10.1 and 12.1V, then you have confirmed your battery is completely toast. Very hard to imagine how they could get that way unless the battery sat for YEARS. Personally, since the vehicle may have other issues, I would attempt to charge it per my instructions. Will probably take you about 2 hours to get it all hooked up, 6 hours to charge and then ? |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by S Keith
(Post 267633)
Terminology:
block = 20 voltages the car monitors comprised of 2 modules module = 6 cell battery, 40 per HV battery pack cell = single 1.2V NiMH cell, 6 per module, 240 per HV battery pack If you're able to monitor block voltages with the diagnostic tool, and all 20 blocks are between 10.1 and 12.1V, then you have confirmed your battery is completely toast. Very hard to imagine how they could get that way unless the battery sat for YEARS. Personally, since the vehicle may have other issues, I would attempt to charge it per my instructions. Will probably take you about 2 hours to get it all hooked up, 6 hours to charge and then ? |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
The only way to charge this one is to do it S Keith's way.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
I had a construction equipment service tech come out to check an electric manlift this week (the guys had left the keyswitch on and it had sat for a couple of weeks without use). The massive 48V battery pack had dropped so low in voltage that it was barely readable and well below the min for the charger to kick in and charge it. He drove another manlift over beside it and hooked the batteries together with jumper cables, (I was waiting on him to pull a beer out and say Hey Hold My Beer) This somehow fooled the charger into seeing enough voltage to start charging. He removed the jumper cables after a few minutes and it continued charging and the manlift worked great after that. Of course these GM Two Mode vehicles are so rare that you might not exactly have one handy to use as a booster LOL. On a construction jobsite there can be hundreds of manlifts as far as the eye can see. Just an interesting tidbit...........................there is probably more than one way to skin this cat.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Hello everyone. So I installed 40 cells after starting I have an error P0C2F motor does not start.(((
The electric motor starts but turns off after a while. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Source of 40 modules?
all module and relay nuts torqued to 48 in-lb? All connections confirmed secure? 12V fully charged and healthy? |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by S Keith
(Post 268184)
Source of 40 modules?
all module and relay nuts torqued to 48 in-lb? All connections confirmed secure? 12V fully charged and healthy? Yes all torque 48 in-lb 12v battery maybe not full charge but I see 14v in my dashboard After starting arrow stand on the middle autostop but after 30-50second drop off |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Chicago38
(Post 268185)
Yes 40 cells now I see 295v
Yes all torque 48 in-lb 12v battery maybe not full charge but I see 14v in my dashboard |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by S Keith
(Post 268186)
Module and pack voltage are not confirmation. What is the source of the 40 modules?
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
Were they from the source I linked? If so, great. If not, you probably bought 40 modules that don't even meet 50% of their rated capacity. Hope not.
Regardless, I don't know what's up. Found this: https://gsi.ext.gm.com/gmspo/mode6/p...iagnostics.pdf My guess is that you've discovered why the car got parked and the hybrid battery went flat. Good luck. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
So now I clear all trouble code and gas engine still not started. I'm used Tech 2 scanner tool and I see electric motor has a rotation speed of 2000rpm when trying to start the engine. It looks like there is no launch signal gas engine.
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Re: P0C17 and P0C18 Tahoe Hybrid 2008
P0C2F Control Module Drive Motor Speed - Engine Speed Correlation
One thing to check is the crankshaft position (CKP) sensor and its wiring. If the crankshaft rotation speed is too different from the calculated speed (from the electric motor speed and transmission ratio), it will give you this P0C2F code. If gas engine speed is less than 1500 RPM, the code will be set when the difference between the CKP sensed engine speed and the calculated engine speed is greater than 1499 RPM for 1 second. If gas engine speed is greater than 1500 RPM, the code will be set when the difference between the CKP sensed engine speed and the calculated engine speed is greater than 249 RPM for 1 second. When the code is set, the hybrid powertrain control module (HPCM) commands the Battery Energy Control Module (BECM) to open the high voltage contactor relays. The code will be cleared when the gas engine speed is greater than 500 RPM and the difference between CKP sensed engine speed and the calculated engine speed is less than 151 RPM. Since you have the Tech 2 scanner, monitor and compare the Engine Speed and the Motor 1 Speed in the HPCM. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Jaime
(Post 268216)
P0C2F Control Module Drive Motor Speed - Engine Speed Correlation
One thing to check is the crankshaft position (CKP) sensor and its wiring. If the crankshaft rotation speed is too different from the calculated speed (from the electric motor speed and transmission ratio), it will give you this P0C2F code. If gas engine speed is less than 1500 RPM, the code will be set when the difference between the CKP sensed engine speed and the calculated engine speed is greater than 1499 RPM for 1 second. If gas engine speed is greater than 1500 RPM, the code will be set when the difference between the CKP sensed engine speed and the calculated engine speed is greater than 249 RPM for 1 second. When the code is set, the hybrid powertrain control module (HPCM) commands the Battery Energy Control Module (BECM) to open the high voltage contactor relays. The code will be cleared when the gas engine speed is greater than 500 RPM and the difference between CKP sensed engine speed and the calculated engine speed is less than 151 RPM. Since you have the Tech 2 scanner, monitor and compare the Engine Speed and the Motor 1 Speed in the HPCM. I have error code C0895 I check fuel pressure and I have fuel. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
DTC C0895 00 Device Voltage – Electronic Suspension Control Module (ESCM) 12V
DTC C0895 03 Device Voltage Below Threshold – PSCM 42V DTC C0895 07 Device Voltage Above Threshold – PSCM 42V DTC C0895 12 Device Voltage Below Minimum Threshold – PSCM 42V Do you have the additional 2 digits after the DTC code to narrow it down to one of the 4 codes above? PSCM = Power Steering Control Module Make sure your 12V battery is fully charged. A low 12V battery or bad wiring to the ESCM could cause that first code. The other codes (03 and 12) can be caused because the Accessory Power Module (APM) has disabled 42V conversion so the PSCM is not reading 42V. Any drive motor codes will disable the 42V conversion by the APM. |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Originally Posted by Jaime
(Post 268218)
DTC C0895 00 Device Voltage – Electronic Suspension Control Module (ESCM) 12V
DTC C0895 03 Device Voltage Below Threshold – PSCM 42V DTC C0895 07 Device Voltage Above Threshold – PSCM 42V DTC C0895 12 Device Voltage Below Minimum Threshold – PSCM 42V Do you have the additional 2 digits after the DTC code to narrow it down to one of the 4 codes above? PSCM = Power Steering Control Module Make sure your 12V battery is fully charged. A low 12V battery or bad wiring to the ESCM could cause that first code. The other codes (03 and 12) can be caused because the Accessory Power Module (APM) has disabled 42V conversion so the PSCM is not reading 42V. Any drive motor codes will disable the 42V conversion by the APM. So what I can do? |
Re: P0C17 and P0C18 Tahoe Hybrid 2008
Keep on troubleshooting.
Found the following: #PIT4820A: (hybrid) Service Power Steering Message With DTC C0895 - keywords 2-mode battery code electric hp2 indicator low mode module power PSCM two-mode voltage 2 - (Feb 16, 2011) Condition/Concern: You may experience a "Service Hybrid Message" on the Drivers Information Center (DIC) followed by a DTC C0895 set in the Power Steering Control Module (PSCM). Recommendation/Instructions: If you experience this message, please check all other module for diagnostic codes before addressing the C0895 DTC. Most likely the code was set due to a hybrid related concern that caused the 300 volt hybrid battery contactors to open which in return will set a C0895 code in the PSCM. Clear the codes with your tool, and then also try disconnecting the 12V battery for some time. |
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