Multiple Codes on Start up
Thread Starter
Instructor
Joined: Jun 2009
Posts: 155
Likes: 20
From: Brentwood Tn
Multiple Codes on Start up
Drove the 2001 (has a 2004 LS6 in it) C5-Z06 a few miles yesterday and notice a noise or catch almost like the ABS was kicking in. This was in a parking lot. Drove 3 miles home with no problem. Planned a little back road drive today, but when I started the car I got multiple codes. P1220 and P1221 TPS sensor 1 & 2, U1064 loss of communication with Drive Control Module, C 1278 Traction control inhibited by PCM, C1278 and one more for reduced engine power. Interestingly they were all H codes. 1. Checked battery it was 12.55 V. 2 Disconnected battery waited about One Beers worth and reconnected. 2. Started car and code were still there but H codes. So I cleared all of them and hooked up the battery charger. Waited about 20 minutes and started it up again. No codes runs fine. Also, checked wires to TPS. Found that the power steering fee line was rubbing on the pulley and fixed that, but it seems unrelated.
The question is would a slightly low battery cause all the codes to stream through the DIC or do I need to keep looking for another cause. The car has been pretty dependable and only has 28,500 miles on it. Motor is stock except for CAI and headers.
The question is would a slightly low battery cause all the codes to stream through the DIC or do I need to keep looking for another cause. The car has been pretty dependable and only has 28,500 miles on it. Motor is stock except for CAI and headers.
Last edited by BTTBSS; Oct 7, 2018 at 08:50 PM.
Thread Starter
Instructor
Joined: Jun 2009
Posts: 155
Likes: 20
From: Brentwood Tn
P1220 still after new Battery 2001 Z06
I started this thread 2 years ago. Since then Replaced the Battery with a new Optima and am learning to use a Tech II. Car was fine until this weekend. I started it up and got a code P1220. Confirmed with my cheap scanner. The DIC indicated all the usual suspects, reduced engine power, no traction control, no active handling. Hooked up the Tech II and checked again. Actually a few times waiting 20 minutes or so between.
Tech II shows TP Sensor 1 at 1.08 V with a closed throttle. WOT 4.34V (gas pedal fully depressed KOEO) TP Sensor 2 shows 3.90 V with a closed throttle and 0.65 V at WOT
Throttle Blade is showing an indicated 15 percent open but the desired amount is 16 percent.
These numbers are close to the FSM recommendations. Should I replace the TP sensor? could do a relearn on the throttle blade but with a 1 percent difference I wonder if it would make a difference. I hate to throw parts at the car if there is an underlying
problem I am missing.
Tech II shows TP Sensor 1 at 1.08 V with a closed throttle. WOT 4.34V (gas pedal fully depressed KOEO) TP Sensor 2 shows 3.90 V with a closed throttle and 0.65 V at WOT
Throttle Blade is showing an indicated 15 percent open but the desired amount is 16 percent.
These numbers are close to the FSM recommendations. Should I replace the TP sensor? could do a relearn on the throttle blade but with a 1 percent difference I wonder if it would make a difference. I hate to throw parts at the car if there is an underlying
problem I am missing.
