wouldn’t start the gas engine
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CF Beginner
Joined: Feb 2026
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wouldn’t start the gas engine
Hi everyone,
This morning my 2017 Chevrolet Volt 2 wouldn’t start the gas engine (outside temperature was about -5 °C / 23 °F). The car runs on electric fine but the gasoline engine didn’t kick in and showed error P16F7.
Has anyone experienced this issue before? Any ideas what might cause it or how to fix it?
Thanks!
This morning my 2017 Chevrolet Volt 2 wouldn’t start the gas engine (outside temperature was about -5 °C / 23 °F). The car runs on electric fine but the gasoline engine didn’t kick in and showed error P16F7.
Has anyone experienced this issue before? Any ideas what might cause it or how to fix it?
Thanks!
Thread Starter
CF Beginner
Joined: Feb 2026
Posts: 2
Likes: 1
ICE was cranking (via motor-generator) but wouldn't start
Symptoms:
ICE was cranking (via motor-generator) but wouldn't start. Error code P16A7 (Ignition Relay Feedback Circuit Low Voltage).
The Breakdown:
The ECM detected voltage, but it was below the required threshold. In my case, the problem was completely resolved without replacing any parts (like the EGR valve).
The Fix (Step-by-Step):
12V Battery Deep Charge (The Primary Fix):
Even if the car "turns on" and the High Voltage (HV) battery cranks the engine, a weak 12V auxiliary battery (in the trunk) causes a voltage drop on the control circuits.
Result: Charging the 12V battery restored the correct voltage levels that the ECM expects to see on the ignition feedback loop.
Clearing High Voltage (HV) Relay Codes:
Low voltage often triggers "latched" faults in the Hybrid Powertrain Control Modules. These errors can keep the HV contactors or the ICE start sequence "locked" even after the battery is charged.
Action: Used an VXDIAG scanner to clear all DTCs, specifically targeting the HV system/Battery codes.
Contact Maintenance:
Used Contact Cleaner on the Black ECM Connector (X1) and cycled the connector several times to ensure a solid connection on Pin 49.
CRITICAL TAKEAWAY FOR THE COMMUNITY:
If you see P16A7, don't jump to replacing the EGR valve or the wiring harness yet!
Check your 12V battery first. A weak 12V AGM is the #1 cause of "ghost" codes in the Gen 2 Volt.
Clear ALL codes. Sometimes the ICE won't fire until the Hybrid/HV error flags are manually reset.
In my case, a full charge and a software reset were 100% successful in bringing the car back to life.
ICE was cranking (via motor-generator) but wouldn't start. Error code P16A7 (Ignition Relay Feedback Circuit Low Voltage).
The Breakdown:
The ECM detected voltage, but it was below the required threshold. In my case, the problem was completely resolved without replacing any parts (like the EGR valve).
The Fix (Step-by-Step):
12V Battery Deep Charge (The Primary Fix):
Even if the car "turns on" and the High Voltage (HV) battery cranks the engine, a weak 12V auxiliary battery (in the trunk) causes a voltage drop on the control circuits.
Result: Charging the 12V battery restored the correct voltage levels that the ECM expects to see on the ignition feedback loop.
Clearing High Voltage (HV) Relay Codes:
Low voltage often triggers "latched" faults in the Hybrid Powertrain Control Modules. These errors can keep the HV contactors or the ICE start sequence "locked" even after the battery is charged.
Action: Used an VXDIAG scanner to clear all DTCs, specifically targeting the HV system/Battery codes.
Contact Maintenance:
Used Contact Cleaner on the Black ECM Connector (X1) and cycled the connector several times to ensure a solid connection on Pin 49.
CRITICAL TAKEAWAY FOR THE COMMUNITY:
If you see P16A7, don't jump to replacing the EGR valve or the wiring harness yet!
Check your 12V battery first. A weak 12V AGM is the #1 cause of "ghost" codes in the Gen 2 Volt.
Clear ALL codes. Sometimes the ICE won't fire until the Hybrid/HV error flags are manually reset.
In my case, a full charge and a software reset were 100% successful in bringing the car back to life.
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