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2002 Ford Taurus P1131 and P0135 O2 Sensor & DPFE Issues - Check Engine Light, Fuel Smell, and Transmission Warning

Model: 2002 Ford Taurus Fault Code: P0135 Posted: 2017-08-26 11:13

I own a 2002 Ford Taurus with the Service Engine Soon (SES) light on. The vehicle is displaying two diagnostic trouble codes: P1131 and P0135. I have already replaced the O2 sensor for Bank 1 Sensor 1, cleaned the EGR valve (which previously had a homemade gasket with no air hole), replaced the DPFE sensor and its hose, and performed a thorough cleaning of the throttle body. Despite these efforts, the check engine light remains on, and I still detect a strong fuel odor inside the cabin. Additionally, the transmission warning light is flashing, though fluid levels are normal. The ABS and brake lights have also come back on—fluids appear fine. I am seeking help to resolve these persistent issues. The car was purchased for a low price, with my husband's brother claiming it would be a $30 fix. I am not a mechanic, despite my name—I'm just a regular person who wants this car to work properly! Could the P1131 and P0135 codes be related? Are there any other underlying issues I should investigate? What about the fuel smell—could it point to an exhaust leak or faulty sensor wiring? And how can I diagnose the transmission warning light if the fluid is fine? I have checked fuses, but I'm not sure which ones are relevant. Any guidance on where to find them would be appreciated.

Related fault codes

P0135P1131

Comments (8)

Anonymous 2017-08-26 11:37

The P0135 code indicates an oxygen sensor heater circuit malfunction in Bank 1 Sensor 1. P1131 typically follows this issue and points to a fuel system problem, possibly related to the O2 sensor or downstream components. Have you checked for any additional diagnostic codes? The brake and transmission warning lights may require a scanner capable of reading vehicle-specific modules (such as the transmission control module). Please check the fuses—especially those related to the engine control system. A common issue is a faulty wiring connection or incorrect sensor installation. Tip: Always use an OEM-quality O2 sensor; aftermarket 'one-size-fits-all' sensors with self-wired connections can cause intermittent faults and misdiagnoses.

Anonymous 2017-08-26 13:07

I replaced the Bank 1 Sensor 1 O2 sensor, and the EGR valve had a homemade gasket that blocked airflow—so I installed a proper one. I also cleaned the throttle body opening and replaced the DPFE sensor. Now only P0131 is showing in the code list, but the fuel smell inside the cabin persists. I bought this car for a bargain price, and my husband’s brother said it would be a $30 fix—turns out he was wrong! I’m not technically trained at all—I just want to get this car running safely.

Anonymous 2017-08-26 13:08

Same as above: O2 sensor for Bank 1 Sensor 1 replaced, EGR valve gasket fixed (was homemade and blocked airflow), throttle body cleaned. DPFE sensor replaced. Current code is P0131, but the fuel smell in the cabin remains a concern. I bought this car cheaply, with my brother-in-law saying it would be a $30 fix—now I’m realizing that’s not true. I'm not a mechanic at all—I just want to get this vehicle working properly.

Anonymous 2017-08-26 13:09

I’ve checked the fuses, but I don’t know which ones are relevant. Where exactly are the engine control-related fuses located in a 2002 Ford Taurus? Can you point me to the fuse box or specific fuse numbers?

Anonymous 2017-08-26 14:18

You mentioned that P0135 and P1131 are now the active codes. Let's focus on P0131 first. According to OBD-II code reference (https://www.obd-codes.com/p0131), this code indicates a lean fuel condition or faulty oxygen sensor reading. Key questions: 1) Did you install an aftermarket O2 sensor with self-wired connections? The symptoms suggest possible wiring issues—please confirm if the replacement was OEM-quality and properly connected. 2) Do you have access to a scanner that can display live data (such as O2 sensor voltage or fuel trim values)? This would help determine whether the sensor is truly faulty or if there's an underlying system issue. Without live data, diagnosing this code accurately is difficult.

Anonymous 2017-08-26 20:54

The current codes are P1131 and P0135. The screen shows freeze frame data: Fuel System - CL-Fault; Fuel System 2 - CL-Fault. Load % = 45.86%, Engine Coolant Temp (ECT) = 91°F, STFT = 7.81%. I hope this helps clarify the issue—no, I did not wire or self-install the replacement O2 sensor.

Anonymous 2017-08-27 05:09

I don’t see P0131 anymore—was that a typo? The P0135 code relates to an oxygen sensor heater circuit failure. To troubleshoot, check fuse #14 (yellow) in the engine bay fuse box and verify 12 volts at the red-highlighted wire on Bank 1 Sensor 1 (B1S1) with the key ON, engine OFF (KOEO). This test helps confirm if the sensor is receiving power. If no voltage is present, it could indicate a wiring issue or blown fuse.

Anonymous 2017-08-30 19:03

How can I properly test an O2 sensor? I replaced Bank 1 Sensor 1, but the code still shows as faulty—could this be due to incorrect installation or a deeper system problem?