P1632 Chevrolet -

Question

My 1998 S-10 2WD 2.2L intermittently will not start when the outside temp is below freezing. Some mornings the truck will start immediately. Others, it will not start no matter how many attempts are made. This problem has existed since I got the truck 2 years ago.

In the past, no DTCs or MIL have ever been set. However, this morning my Actron scan tool indicated a P1632 "theft deterrent system--fuel system disabled" code. This was indicated directly following a start attempt. I cleared the code. The code would not reset even though the engine still would not start. During no-starts, the ignition system produces a strong spark.

The fuel pump cycles normally for 2 seconds when the ignition is turned on.

Again, this no start ONLY occurs when the ambient temp is below freezing. Any help offered will be appreciated.

Answer 1

P1632 Theft deterent system fuel disabled

The excessive cranking and a no start can also set this code. This condition has a lot to due with the crank position sensor (CKP). Cheverolet had a TSB about this condition , what happens is the PCM reset the CKP learn position and the theft deterrent . You can either replace the ECM or reprogram the ECM for this condition. what needs to be done  also is to perform a CKP variation relearn. TSB # 87-65-06A.