Intermittent "Service Engine Soon"

[pns0ccc]

SYS light on DIC becomes active for a few days and then goes out for a few days. The code is P0157 (low voltage) or bank 2 sensor 2 Oxygen sensor. Replaced right rear 02 sensor and problem still repeats. Checked exhaust manifold for leaks with none found. Local Corvette West repair center believes could be EPROM problem. Any ideas?

 

[jmccloud]

SYS light

Frequently the SYS light indicates a poor battery condition. My '95 SYS light would blink a few times under hard accel but threw no codes. Discovered the battery was original (this was in 2003) so replaced the battery. Haven't seen the SYS light since.
Also, you can do a search (see tab above) on SYS and get lots of input.
Hope this helps.

 

[pns0ccc]

I've replaced the battery in November and cleared the P0157 at the same time. SYS still returns the same code and clears after three consecutive drive trips.
Checking the H02S sensor with a scanner the voltage is within normal operating parameters. My next step is to remove the exhaust system on the right side and check the wiring from the sensor to the PCM for grounding or contamination and replace the exhaust gaskets.
Another item for me to check is for lean injectors but I will have to take the car in to a shop for that unless someone has an idea for at home testing. Thanks

 

[AIRBUS]

SYS light on DIC becomes active for a few days and then goes out for a few days. The code is P0157 (low voltage) or bank 2 sensor 2 Oxygen sensor. Replaced right rear 02 sensor and problem still repeats. Checked exhaust manifold for leaks with none found. Local Corvette West repair center believes could be EPROM problem. Any ideas?

I had the same problem: replaced O2 sens - no joy.

Replaced EGR valve - that was it.

Good luck.

 

[pns0ccc]

Removed the EGR valve, light minimal deposits, scraped with small screwdriver and nothing broke loose or came out. Depressed diaphragm on EGR assembly, air released and spring returned to normal position. Troubleshooting continues.