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2001 Dodge Ram 2500 5.9L Gas Engine P0201 Code: Diagnosing #1 Injector Circuit Fault

Model: 2001 Dodge Ram 2500 Fault Code: P0201 Posted: 2017-07-09 14:42

My 2001 Dodge Ram 2500 with a 5.9L gasoline engine is showing Diagnostic Trouble Code P0201, indicating an issue with the #1 injector circuit. I've already tested all injectors using an ohmmeter and found they read 12 ohms, which falls within specification. I also performed continuity tests on both the injector driver wires from the Powertrain Control Module (PCM) to the injector connector, as well as the wiring between the ASD relay and the injector connector — all results came back good. Given this, I'm now considering a faulty PCM as the root cause, though I'm not certain. Has anyone else encountered this issue? Are there any other diagnostic steps or known causes for P0201 on this model?

Related fault codes
P0201
Comments (3)
Anonymous 2017-07-09 15:19

Is the code intermittent or does it set immediately when you turn the ignition on? Most cases of P0201 are intermittent. Have you checked how long the code has been present? Use a noid light to observe injector pulse behavior — check if the signal flashes, stays on, or never activates. Try gently wiggling the injector harness at the connector; often early damage occurs in the first few inches of wiring.

Anonymous 2017-07-09 17:00

The P0201 code returns after approximately two minutes of engine operation. I performed a wiggle test, but it didn’t resolve the issue. However, when someone manually pulls on the #1 injector connector while the engine is running, the code changes — this suggests a potential intermittent connection or harness fault.

Anonymous 2017-07-09 17:21

If the P0201 code persists, removing the injector connector should not change the behavior. I recommend performing a noid light test to verify if the PCM is sending the correct voltage signal to the #1 injector circuit. The test involves checking for proper pulse when the ignition is on — observe both the 12V battery voltage (KOEO) and the drop in voltage when the driver grounds the injector circuit. The #1 front injector connector, located on the driver's side, should be tested specifically.