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2002 Dodge Dakota 3.9L V6 P0132, P0172, P0301, P0455 - O2 Sensor Codes Persist After Replacement and Head Work

Model: 02 Dakota 3.9l v6 Fault Code: P0132 Posted: 2016-08-23 09:34

I'm experiencing persistent OBD2 trouble codes: P0132, P0172, P0301, and P0455 on my 2002 Dodge Dakota with a 3.9L V6 engine. I've already had the oxygen sensors replaced, and my brother's shop installed new cylinder heads—yet the codes remain. I've thoroughly inspected all hoses for leaks and replaced the purge solenoid. The vehicle runs smoothly at times but occasionally behaves as if the choke is stuck, even though it has electronic fuel injection (EFI). I'm seeking advice on what could be causing these persistent issues. Any insights would be greatly appreciated. Thanks, Paul

Related fault codes
P0132
Comments (6)
Anonymous 2016-08-23 10:57

First and foremost: do not replace parts solely based on a diagnostic code. O2 sensors are 'messengers'—they don't cause problems, they only report data. P0132-1/1: O2 Sensor Shorted to Voltage — indicates a wiring issue with B1S1 (Bank 1, Sensor 1). Did you use a non-original or improperly installed oxygen sensor during replacement? P0172-1/1: Fuel System Rich — perform a fuel pressure test under KOEO conditions. Observe the drop in pressure over five minutes—any significant drop may point to a leaking injector or other fuel system component. P0301: Misfire in Cylinder #1 — check if cylinder #1 is firing properly. Look for spark and inspect the plug condition (wet, dry, black, tan). A faulty injector could be the root cause. P0455: EVAP System Large Leak — perform a vacuum test by pinching off the vacuum line to the purge valve (near the brake booster) to isolate whether the system is leaking. This suggests an issue with either the purge or LDP systems.

Anonymous 2016-08-23 19:09

I did not replace the O2 sensors myself—the shop my brother took it to handled that. The vehicle is a California emissions model, which includes multiple oxygen sensors. I noticed the plug wire for cylinder #1 was not properly connected. What do you mean by 'wiring problem with B1S1'? I will test the vacuum line to the purge valve tomorrow. No history of fuel delivery issues—no stalling or sudden gas consumption. I'll perform a fuel pressure check when possible. I'm doing all diagnostics in my driveway due to lack of access to a garage. Thanks, Paul

Anonymous 2016-08-24 06:50

"Wiring problem with B1S1" refers to Bank 1, Sensor 1 — the O2 sensor located on the exhaust pipe before the catalytic converter, on the side of the engine where cylinder #1 is situated. This sensor monitors exhaust gas composition and provides feedback to the ECU. Are you still seeing P0132? If so, it may point to a wiring fault or improper installation.

Anonymous 2016-08-24 10:26

It might have been as simple as the #1 spark plug wire boot being pushed past its end—resulting in an incorrect connection. After fixing this, I no longer see any codes. I've been troubleshooting for three months and it turns out to be something basic. I'll drive around for a while to monitor performance, try an injector cleaner, and assess whether the issue resolves. Thanks again, Paul.

Anonymous 2016-08-24 10:29

Also added a new clamp on the vacuum line connected to the master brake cylinder to ensure no leaks are present.

Anonymous 2016-08-24 12:27

A failing spark plug will trigger P030x misfire codes and cause O2 sensor readings to rise, leading to a rich fuel condition (P0172). Remember: diagnostic codes do not always indicate a faulty part—O2 sensors are simply reporting tools. Let's hope the EVAP leak (P0455) doesn't reappear. For injector cleaning, I use Seafoam as my go-to product.