A grounded signal or return wire from the #2 fuel injector can cause overfueling, leading to a constant spray of fuel from that injector. This directly results in the P0202 diagnostic trouble code (DTC) being triggered. The issue may stem from poor electrical connections, damaged wiring, or corrosion at ground points. In such cases, the engine control module (PCM) detects abnormal signal behavior and logs the fault.
No — the issue is likely in the wiring harness between the #2 fuel injector and the PCM, not a grounding problem.
Perform a fuel pressure test to record baseline psi. Then, with the engine off (KOEO), monitor how quickly the pressure drops. If it decreases by more than +5 psi, this suggests a leak or faulty injector — check if the #2 spark plug is wet, which may indicate excessive fuel delivery.
Yes, a grounded return signal would cause overfueling. You might also notice white smoke from the exhaust with a gasoline-like odor. A faulty PCM driver circuit is another possibility. Do you have a DC voltmeter to check for voltage on the #2 injector control wire at the PCM during KOEO?
kev2 wrote: Fri Feb 17, 2017 9:49 am Yes — a grounded signal/return would overfuel, causing the #2 injector to constantly spray. I'm experiencing the same issue. I found that the wires at the pigtail were open and touching. I wrapped them with electrical tape, but the P0202 code persists even after resetting. What other troubleshooting steps should I try?
A bad ground connection from the battery could potentially cause a P0202 code. Recently, I inspected my truck and found that one of the frame grounding wires had oil buildup from the power steering pump, while another ground wire was clogged with dirt and mud—this may have compromised electrical integrity.