The P2157 code indicates that the engine control module has detected a voltage level higher than normal in the power supply circuit for fuel injector group D. This typically suggests an electrical short to a higher voltage source or a failure within the circuit's components.
Chafed or damaged wiring in the injector harness shorting to a 12V power source.
An internal electrical failure or short within one of the injectors in group D.
Corrosion or contamination in the electrical connectors causing improper voltage readings.
A failing voltage regulator or alternator providing excessive voltage to the entire electrical system.
A failure in the engine control module's internal voltage monitoring or switching circuitry.
No. While the PCM is listed as a possible cause, P2157 is far more commonly caused by wiring shorts or injector failure. The PCM should only be replaced after the wiring and injectors have been thoroughly tested and ruled out.
Yes, if an injector develops an internal short that affects the supply voltage of the shared circuit, it can trigger a group-level code.
The vehicle may be drivable, but it will likely suffer from poor performance and increased emissions due to misfiring cylinders, which can eventually damage the catalytic converters.