I'm New Here
Feb 14, 2014
Canada b langley
1999 ls1 vert
Hey guys I bought a 1999 corvette and i new it had a few problems but now it's stuck in reduce engine power mode, and when you turn key on ac the dash and lights flicker, also it doesn't always turn dash on you have to turn the key on back and forth a bunch of times for it to initialize

I've check under the battery for leaks and nothig
Also checked throttle body connectors for corrosion and nothing major but I cleaned em, computer is also clean

The car is a 1999 convertible ls1 with Texas speed heads, cam, cold air intake, borla exhaust and so I'm told it's EFI live tuned so plz suggestion how to get it out of this mode

Here are the codes
P1222 hc
C1278 c
B0333 hc
B0338 hc
B0446 h
B0032 hc
P1221 hc
P1120 hc
B0502 hc
Any tips would be appreciated I also checked the front ground connectors and cleaned them but didn't so anything
If I clear the codes through the DIC it fires up and runs fine for about 10 seconds then goes back into reduce engine power mode?
P1332 - Not sure what this is as I can't find the listing
P1222 - Not sure, closest one I can find is P1221
P1221 - Throttle Position (TP) Sensor 1‐ 2 Correlation/PCM/Engine Controls, Cruise Control

C1278 - TCS Temporarily Inhibited By PCM/EBCM/Antilock Brake System
I believe this is the one giving you the hassle.

B0333 - Outside Air Temp Sensor Open/HVAC/HVAC Systems Automatic
B0338 - Inside Air Temp Sensor Open/HVAC/HVAC Systems Automatic
B0446 - Right HVAC Actuator Out of Range/HVAC/HVAC Systems Automatic
B0032 - Did not find this one
P1120 - Throttle Position (TP) Sensor 1 Circuit/PCM/Engine Controls, Cruise Control
B0502 - RH DRL Relay Circuit/BCM/Lighting Systems

There you have it. Most likely just the code C1278 giving you the issue.

Did you recently wash your car? You may have gotten water in a connector, either at the ECBM or Wheel Sensor. I also ran across someone who got water in the MAF sensor plug, they blew it out and everything was back to normal.
Ok i cleared them all and got these

B0022 hc
B0502 hc

Tcs 1278c

P1120 hc
P1221 hc

So something with the traction control could be limiting it from revving?

I cleaned the maf today
Thanks a lot for the help btw

If you have time call me at the shop on Tuesday and I will walk you through a few test's , and see if we can shed some light on the problem .


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