Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2009TAHOE BASE, 4.8 CREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 12 (HYBRID ENGINE CONTROLS - DTC P181C TO DTC P2797)DTC P1A88CIRCUIT/SYSTEM VERIFICATION
2009 Chevrolet Tahoe Base, 4.8 C
Circuit/System Verification
2009 Chevrolet Tahoe Base, 4.8 CSECTION Circuit/System Verification
WARNING: This page is about a different variant/trim than selected.
- This DTC can set as a result of conditions external to the APM. Before attempting to diagnose this DTC, ensure the following conditions have not been encountered:
- High voltage contactor relays opening any time the APM is doing 42 volt conversion.
- The high voltage system is greater than 390 volts or less than 216 volts during 42 volt conversion. Extreme cold weather conditions may occasionally cause the high voltage system to be greater than 390 volts.
- The 12 volt circuit is less than 6.7 volts during 42 volt conversion.
- A short circuit condition on the 42 volt circuit which causes the APM to produce greater than 60 amps.
- If any of the above APM-external conditions have occurred, diagnose the conditions as applicable and clear the DTC Information. No further diagnosis of this DTC is required.
- If none of the above APM-external conditions have been encountered, continue with Circuit/System Verification.
- Turn the ignition key to the RUN position. Ensure that the high voltage contactor relays close. Do not go to START.
- If the high voltage contactor relays do not close, diagnose the DTC or symptom that is preventing them from closing before attempting to diagnose this DTC.
- Test for DTC P1A88.
- If the diagnostic is set as Last Test Failed/Current, replace the APM.
- Start the engine.
- Test for DTCs P1A89, P1A8A and P1A8C.
- If any of the above diagnostics are set, diagnose those first.
- After the engine has started, retest for DTC P1A88.
- If the diagnostic is set as Last Test Failed/Current, proceed to Circuit/System Testing.
- If the diagnostic is set as Last Test Passed, the external condition that set this DTC is no longer present. Clear the DTC Information. No further diagnosis of this DTC is required.
IMPORTANT:
Do not turn the ignition to START.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.