WHAT did I do???
04-06-2016, 06:13 PM
#1
WHAT did I do??? My 1998 Z28 had a very high idle (1800rpm's) and the car is old, like me 
.
So I replaced the TPS, MAF & IAC modules and now I have a good idle but my ABS INOP light came on upon my first start up after the repairs. I also removed the AIR injection tubes from the exhaust manifolds and installed block off plates. I checked for codes with my Torque app on my cell phone and found faults but no codes. The MAF is GM. The IAC & TPS are aftermarket, I don't have the old TPS because it fell apart when I tried to remove it. The abs fuse is good. Can someone help me to troubleshoot this issue?
.So I replaced the TPS, MAF & IAC modules and now I have a good idle but my ABS INOP light came on upon my first start up after the repairs. I also removed the AIR injection tubes from the exhaust manifolds and installed block off plates. I checked for codes with my Torque app on my cell phone and found faults but no codes. The MAF is GM. The IAC & TPS are aftermarket, I don't have the old TPS because it fell apart when I tried to remove it. The abs fuse is good. Can someone help me to troubleshoot this issue?
. Electronics can do strange things. 
04-07-2016, 06:45 PM
#5
So I've been reading and people talk about a TPS reset and/or relearn. I've never heard of such a thing, how is this done? I read in my Service Manual that when replacing the TPS you need to hook up the scan tool, I don't have the Chevrolet scan tool. 
04-08-2016, 03:12 PM
#7
12 Second Club
Join Date: Sep 2005
Location: Bucks County, Pa.
Posts: 4,273
Likes: 0
Received 0 Likes
on
0 Posts
Yes, if it does not go away after a battery disconnect (and the code being cleared with a scan tool of some sort), then it may just be coincidence that the ABS light showed up at this time, and you might actually have an ABS problem of some type. 
Check the ABS electrical connectors at your front hubs and rear axle to make sure they are connected, clean, and not shorted out.
Check the ABS electrical connectors at your front hubs and rear axle to make sure they are connected, clean, and not shorted out.
Trending Topics
04-08-2016, 03:31 PM
#8
Staging Lane
Join Date: Mar 2014
Posts: 95
Likes: 0
Received 0 Likes
on
0 Posts
Tps reset is in the forum somewhere. Ign off, disconnect tps iac and maf (just for good measure), then ign on (do not turn engine over) for 15 sec or so, ign off, reconnect everything, turn ign on then start. I think I said it right.
04-09-2016, 05:01 AM
#11
Idle Relearn.
After disconnecting the battery for more than 30 minutes:
Automatic transmission:
1 Turn off the ignition
2 Restore the PCM battery feed
3 Turn Off the AC controls
4 Set the parking brake and block the drive wheels
5 Start the engine
6 Allow the engine coolant temperature to reach 176 degrees F
7 Shift the transmission selector into the drive range
8 Allow the engine to idle for 5 minutes
9 Turn on the AC controls (Omit for 2000-02 model)
10 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
11 Shift the transmission selector into Park
12 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
13 Turn off the AC controls (Omit for 2000-02 model)
14 Allow the engine to idle for 5 minutes
15 Turn off the engine for 15 seconds
Manual Transmission:
1 Turn Off the ignition
2 Restore the PCM battery feed
3 Turn Off the AC controls
4 Set the parking brake and block the drive wheels
5 Transmission in neutral
6 Start the engine
7 Allow the engine coolant temperature to reach 176 degrees F
8 Turn on the AC controls (Omit for 2000-02 model)
9 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
10 Turn off the AC controls (Omit for 2000-02 model)
11 Allow the engine to idle for 5 minutes
12 Turn off the engine for 15 seconds
After disconnecting the battery for more than 30 minutes:
Automatic transmission:
1 Turn off the ignition
2 Restore the PCM battery feed
3 Turn Off the AC controls
4 Set the parking brake and block the drive wheels
5 Start the engine
6 Allow the engine coolant temperature to reach 176 degrees F
7 Shift the transmission selector into the drive range
8 Allow the engine to idle for 5 minutes
9 Turn on the AC controls (Omit for 2000-02 model)
10 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
11 Shift the transmission selector into Park
12 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
13 Turn off the AC controls (Omit for 2000-02 model)
14 Allow the engine to idle for 5 minutes
15 Turn off the engine for 15 seconds
Manual Transmission:
1 Turn Off the ignition
2 Restore the PCM battery feed
3 Turn Off the AC controls
4 Set the parking brake and block the drive wheels
5 Transmission in neutral
6 Start the engine
7 Allow the engine coolant temperature to reach 176 degrees F
8 Turn on the AC controls (Omit for 2000-02 model)
9 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
10 Turn off the AC controls (Omit for 2000-02 model)
11 Allow the engine to idle for 5 minutes
12 Turn off the engine for 15 seconds
04-10-2016, 10:59 AM
#12
So I replaced the TPS with an AC Delco and no more codes with it but I still have that ABS inop light on. When I removed the Air pump and hoses is it possible I disturbed something to cause this light to come on? It was not on before I started the work, coincidence possibly but not likely. 
04-10-2016, 12:48 PM
#13
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
So I replaced the TPS with an AC Delco and no more codes with it but I still have that ABS inop light on. When I removed the Air pump and hoses is it possible I disturbed something to cause this light to come on? It was not on before I started the work, coincidence possibly but not likely.
04-10-2016, 04:13 PM
#15
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
04-10-2016, 08:15 PM
#17
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
