Questions and Answers

Plymouth Acclaim Code 51 Q. I own a 1991 Plymouth Acclaim with a 2.5 liter engine, automatic transmission, 150,000 miles, fuel injection, power steering, front wheel drive, A/C and cruise control. My problem is that the Check Engine Light (CEL) comes on after 10 to 15 minutes of driving. When the car is turned off and back on again, the light goes off, but when I drive it, it again will turn back on after 10 to 15 minutes.

When I tested, it shows code 51 - lean condition. I replaced the oxygen sensor (the light did not appear for a few days, but then it turned on again as before). Then I replaced the Throttle Position Sensor (TPS), Manifold Pressure/Vacuum (MAP) sensor, Temperature sensor, catalytic converter and replaced the vacuum lines.

Even after all of these repairs, the light continues to come on. I do not know what the next step is. Can you help me? I am desperate.

Thank you,
Victor

A. Have you tried replacing the fuel filter? A restricted fuel filter can also throw a code 51.

You might also have a bad O2 sensor. With a voltmeter check the voltage output of the O2 sensor at the dark green/black wire. It should fluctuate between 0.1 to 0.9 volts. if it remains steady, it needs to be replaced.