Hey all, first post. Usually the ole google and forum search is all it takes but not this time.
I have a 98 w/ 5.7 Vortec. When I look at the OBD scan tool I see on cold start, as engine warms up, it goes from OL to CL-Fault for both banks. Is this normal? Anyone with a scan tool want to plug in and take a look at their truck?
The reason I ask if its normal is that perhaps early OBDII stuff works this way, though I'm aware newer cars do not.
Some background: Recently I had a CEL for P0154 [bank 2 sensor 1 low voltage] so I decided to swap in a pair of new Denso upstream O2 sensors for the old girl. Code fixed, trucks runs well things seem fine.
BUT, this got my watching things in the OBD scanner [wanted to make sure voltage was bad in the one sensor and checked with tool to confirm]. I also noticed my coolant temps were low so a new t stat went in [old one was clearly failing open] and i plugged in scan tool a number of times while driving to keep tabs.
My understanding of CL-Fault is that one bank will have an issue [say bad O2] and then steal data from known good bank. but that only produces cl-fault for one bank and the other runs in CL as it should. I get CL-Fault on both banks so what gives?
All my fuel trims, sensors voltages, etc look spot on. no anomalies.
any ideas?
I have a 98 w/ 5.7 Vortec. When I look at the OBD scan tool I see on cold start, as engine warms up, it goes from OL to CL-Fault for both banks. Is this normal? Anyone with a scan tool want to plug in and take a look at their truck?
The reason I ask if its normal is that perhaps early OBDII stuff works this way, though I'm aware newer cars do not.
Some background: Recently I had a CEL for P0154 [bank 2 sensor 1 low voltage] so I decided to swap in a pair of new Denso upstream O2 sensors for the old girl. Code fixed, trucks runs well things seem fine.
BUT, this got my watching things in the OBD scanner [wanted to make sure voltage was bad in the one sensor and checked with tool to confirm]. I also noticed my coolant temps were low so a new t stat went in [old one was clearly failing open] and i plugged in scan tool a number of times while driving to keep tabs.
My understanding of CL-Fault is that one bank will have an issue [say bad O2] and then steal data from known good bank. but that only produces cl-fault for one bank and the other runs in CL as it should. I get CL-Fault on both banks so what gives?
All my fuel trims, sensors voltages, etc look spot on. no anomalies.
any ideas?
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