C5 corvette (1999) reduced engine power
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Joined: Dec 2018
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C5 corvette (1999) reduced engine power
Hey guys I have a 1999 corvette, the car got a little front end damage and the core support was fixed as well with a new radiator, water pump and belt. Was pulling the car out to drive it after everything was put back together and me being stupid Reved it up and hit the rev limiter and nothing happened at first. Then the car just kinda down idled and I had no throttle response what so ever car was running with a choppy idle and would not accelerate at all. I cut the car off then back on and the max I could get the RPMs to was 2600. It seem the car had went into a limp mode. I disconnected the battery and did a number sort of things to try to get it to reset, nothing worked. I took it the shop and had the codes checked. Codes were as followed:
PCM :
P1220
P1221
TCS:
C1225
C1278
C1790
BCM:
BO432
BO502
BO503
BO507
BO508
B2482
B2527
B2588
B2593
B2723
SDM:
U1096
RDCM:
B2283
B2285
U1064
So, with that being said it’s throwing a lot of codes but the mechanic said it’s the throttle body that’s causing the driving problem so he ordered a used throttle body to replace it with put it on there and it still did not work. There was also a brand new TPS sensor that was put on to still no luck. He also said he did a idle relearn procedure on the car and that did nothing either. Nothing I do will make it drive nor operate normally. I paid his bill and now I have it sitting back in the garage. Please help I am at a lost point.
PCM :
P1220
P1221
TCS:
C1225
C1278
C1790
BCM:
BO432
BO502
BO503
BO507
BO508
B2482
B2527
B2588
B2593
B2723
SDM:
U1096
RDCM:
B2283
B2285
U1064
So, with that being said it’s throwing a lot of codes but the mechanic said it’s the throttle body that’s causing the driving problem so he ordered a used throttle body to replace it with put it on there and it still did not work. There was also a brand new TPS sensor that was put on to still no luck. He also said he did a idle relearn procedure on the car and that did nothing either. Nothing I do will make it drive nor operate normally. I paid his bill and now I have it sitting back in the garage. Please help I am at a lost point.
Last edited by AJ Tedder; Dec 29, 2018 at 09:58 PM.
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
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2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
take a look at the wiring to the throttle body sensors, I had one of the pins open up on my tps plug and caused the same problem you are having... also inspect the tac module and connectors
Last edited by StingrayRebel; Dec 29, 2018 at 11:45 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,561
Likes: 4,030
From: Cape Coral, Florida
If you have NO throttle response whatsoever check the THROTCONT fuse in the under hood fuse box...I believe it’s #17 if I’m not mistaken !!…."normally" it will throw P1518 DTC if blown but see what you have !!...also if you have a DVOM I can show you how to check the TPS sensor !!
Last edited by C5 Diag; Dec 30, 2018 at 12:00 PM.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
What happens when you CLEAR all the DTC codes ??
Does it temporarily run OK ?
Clear all the codes------Before stsrting the engine READ them again--These codes typically are the hard codes that are causing the issue
IF they all disappear after you clear them and read them again before starting then that wold point to something else
Do all the interior fuctions still work ? electric windows--door locks---dash info-- door chimes---radio ?
Typically this means you have a BCM issue either a bad BCM or faulty wiring
The BCM is intregal in many of your car's functions --It sorts out information and is involved with your TRACTION CONTROL system and your Throttle Body -----The TC system uses the T Body to control wheel spin
Being you have TC codes and BCM codes and communication codes (U codes) to me points to the BCM which is involved with all these fuctions
Does it temporarily run OK ?
Clear all the codes------Before stsrting the engine READ them again--These codes typically are the hard codes that are causing the issue
IF they all disappear after you clear them and read them again before starting then that wold point to something else
Do all the interior fuctions still work ? electric windows--door locks---dash info-- door chimes---radio ?
Typically this means you have a BCM issue either a bad BCM or faulty wiring
The BCM is intregal in many of your car's functions --It sorts out information and is involved with your TRACTION CONTROL system and your Throttle Body -----The TC system uses the T Body to control wheel spin
Being you have TC codes and BCM codes and communication codes (U codes) to me points to the BCM which is involved with all these fuctions
