Hi everyone just purchased this truck, bought it unseen nonrunning 133k miles. i was hoping it was a dead acc battery or fuel pump after doing so quick homework, not the case. i got the battery replaced checked the fuel pump it is good. trucks electric start runs for about 10 to 15 seconds, I will check for spark first thing in the morning. i was hoping to get some responses of what else it could be with the codes.
p0521 oilpressure switch range
p0ac4 hybrid pcm
p0700 trans control mil request
p 0963 trans pcs a high circut
p0967trans pcs B high
p0971 trans pcs c High
p2720 trans pcs D low
p2729 trans pcs E Low
The only code on here that catches my eye is p0521 but i know a gas vehicle will run with that code. I have always wanted to get into a hybrid. hopefully this works out. Any help would be greatly appreciated.

 

Repeated attempts to start the vehicle will deplete the HV battery.

 

Here's some analysis based on the only hybrid info I have for a Tahoe:

• P0AC4 Hybrid Powertrain Control Module Requested MIL Illumination
  • This one is a result of the other P0521 code being set. Resolve the other and this should clear.
• P0700 Transmission Control Module (TCM) Requested MIL Illumination
  • This one is a result of the other transmission codes being set. Resolve the rest and this should clear.

• P0521 Engine Oil Pressure (EOP) Sensor Performance
  • Possibly bad sensor. The ECM is not seeing expected pressure readings based on the current engine conditions. While you're replacing it, also replace the oil filter screen that goes in here. It supplies oil to the Active Fuel Management system. Do you notice the oil pressure gauge being slow to react, or not working at all? This sensor is at the rear drivers side of the Valve Lifter Manifold Assembly (under intake manifold).

• P0963 Line Pressure Control (PC) Solenoid Control Circuit High Voltage
  • This DTC sets when PCS1 has been detected to be shorted to power or open circuited.
• P0967 Clutch Pressure Control (PC) Solenoid 2 Control Circuit High Voltage
  • This DTC sets when PCS2 has been detected to be shorted to power or open circuited.
• P0971 Clutch Pressure Control (PC) Solenoid 3 Control Circuit High Voltage
  • This DTC sets when PCS3 has been detected to be shorted to power or open circuited.
• P2720 Pressure Control (PC) Solenoid 4 Control Circuit Low Voltage
  • This DTC sets when the PCS4 control circuit has been detected to be open circuit or shorted to power.
• P2729 Pressure Control (PC) Solenoid 5 Control Circuit Low Voltage
  • This DTC sets when the PCS5 control circuit has been detected to be open circuit or shorted to power.

Check the wiring to the transmission and the connectors at the back passenger side of the transmission above the 4th oil pan bolt (from front to back).
If you need a new Transmission Control Module and Valve Assembly, I believe the correct part is this one:
Transmission Valve Body / TCM / Transmission Control Module 2ML70 (M99) Factory Part Nos. 24256374, 29543915

 

Thanks Jamie, i wouldnt have figured the oil pressure sensor causing a no start issue but that will be my next step after figuring out if it has spark. I have replaced plenty of them but usually on gas motors with higher miles. then to the trans wiring. ill post findings tomorrow evening. really appreciate the pointers

 

thanks S Keith, i have read almost all the postings on this forum, just didn't see one that had the issue with mainly trans codes. thanks for looking out for the new guy.

 

getting different codes every time we clear them. except for the trans codes are always there.300v battery is currently at 254v losing 4v per start attempt. something im finding strange i have 13 v at the ice battery but at the hybrid terminal i have 10.6. im going to look into the trans codes and go from there. if anyone else has any ideas that might help it would be greatly appreciated.

 

288V is dead empty. You need to make plans to charge the battery.

 

S keith, is there a way to charge that battery?

 

You'll need a high voltage power supply and a diode.

HLG-120H-C350A power supply and a D1NK60-5070 diode. Make 120VAC cable for the power supply, fabricate leads and install the diode (to protect the power supply - don't want battery voltage pushing back on the PSU when it's off). You'll have to open the battery up, attach the power supply to the battery side of the relays (main terminals are isolated when car is off), energize charger, install safety plug and charge for 115 to 125 minutes. This should restore the battery to 10% of rated capacity.

 

Found the pics...

Positive:



Negative: