2000 Pontiac Montana Engine Codes P0171 and P0742

JPK1200

MEMBER
2000 PONTIAC MONTANA
6 CYL
FWD
AUTOMATIC
108,000 MILES

I have 2 computer codes registering now, 1st is P0742 TCC Stuck On and the 2nd P0171 Fuel trim bank condition. I just did a tune up on the vehicle including wires along with brakes and a tie rod.

My questions are this;
1. Could these two code be related meaning if I fix one the other will go away?
2. Could flushing the transmission help with the TCC soleniod being stuck on or do I need to replace it?
3. If I need to replace the TCC soleniod where can I find instruction on doing the repair?
4. For the P0171 code how do I determine which of the 3 oxygen sensors is reading faulty? Could reseting the computer eliminate this all together where I just did a tune up and the rear plugs where replaced for the first time since new (108K miles)?

1 Reply

TURBOGSR

MEMBER
1 POST

The code for p0171 does not necessary means that your 02 sensor is bad. Your o2 is just reading too much air passing. So which means that you have a leak somewhere within your intake manifold area. Usually its your pcv lines. Find your pcv line and check for hole or leak in the pcv hose, or any vacuum line. The second cause is your MAP sensor (mass air flow). Locate your MAP sensor and take it out and clean it using cotton swab dipped in isopropyl alcohol (regular rubbing alcohol) clean the sensor and remount. After all the above is replaced with new parts or clean, then take your car to autozone or any car parts store and have them reset/clear your ecu/ecm its free, unless you have your own obd scanner.