1996 Chevrolet 2500 Pickup Q&A
1996 Chevrolet 2500 Pickup Question: code po 172 keeps coming up! tried to fix it, no luck yet!!
po172, system too lean bank one, code keeps coming up. i have cleaned the MAF sensor, installed a new air filter, cleaned my EGR valve!! code continues to come up!! any advice? i did all these things one day and the light went off when i was going to scan my truck to see if it was going to go away. now in my process of going to the auto store the light went out!! scanned it anyway and NO codes were shown!!! go figure!!! help!! - thor1779
Tests/Procedures: 1. Check fuel pressure at idle and under load. Idle pressure should be about 55-57 PSI. Loaded fuel pressure should climb to about 60-65 PSI. 2. Verify the Coolant Temperature Sensor (CTS) is accurate. 3. Check the Mass Air Flow Meter (MAF) for about 4-7 Grams Per Second (GPS) at idle. 4. If all OK, remove the plenum, check for intake "washing" caused by a leaking fuel pressure regulator. Of course you need a scanner that can read serial data to see these specs. - PARTS GUY
172 is a rich code, not lean. items like clogged air filters, leaking injector, mass air flow, coolant sensor are some possibilities. you need a shop that can acess the history codes and freeze frame data to see which sensor is reading out of spec and give you a solution. Roy - mastertech6371