1997 Ford Taurus check engine light and codes

  • 1997 FORD TAURUS
  • 3.0L
  • V6
  • FWD
  • 120,500 MILES
The check engine light is on in this car. I got 2 codes p1138 and p1000. I recently replaced the upstream front O2 sensor and the check engine light went out briefly for 2 or 3 days. Should I replace the downstream O2 sensors both at the same time. Would this solve my problem?
Do you
have the same problem?
Monday, October 6th, 2014 AT 2:24 PM

1 Reply

P1138 - O2 Sensor Heater Circuit Low Voltage (Bank 1 Sensor 2)
P1000 - Monitor Testing Not Complete

The first code is typically caused by a grounded wire, but you need a scanner to view live data to know for sure. A grounded wire will give you a 0.0 volt reading and that code will set. If you find the voltage is higher than 0.0 volts but stays below about 0.5 volts, there's something causing a fuel / air mixture problem and the sensor and fault code are just reporting what it sees. The sensor after the catalytic converter just monitors the efficiency of the converter. It's voltage is expected to switch between below and above half a volt perhaps once or twice per minute. If it stays in one state too long, that would set a fault code related to "catalytic converter efficiency". Your code is quite different, so I'd check the wiring before I'd replace the sensor.

There are many self-tests run by the Engine Computer. The second code just means one of those tests has been suspended because two or more things are compared, based, in part on the readings from that oxygen sensor. The computer knows it can't rely on that sensor's readings so it can't use those values for comparison for other tests.
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Tuesday, October 7th, 2014 AT 2:26 AM

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