mmg

Been having this issue, on and off, since late last summer before I put the car away for winter. Still there when I pulled it out this week, so asking for advice. I know there's a ton of threads on this, but none I've seen appear to solve. Maybe I missed some, so sorry in advance.

Here's my codes

U1040 H
B0432 HC
P0480 HC
P1571 H
P1652 H
P1689 H

These are the ones that are left after I cleared all codes and then restarted twice...on the second start the service ride control/shocks inoperative/80mph stuff came back on again with the above codes.

The first time I read them, before I cleared them, included these:

B2605 H
B2606 H
B2607 H
B2860 H
B2265 H
C1277 H


It's a 2002 automatic with F45. I pulled and cleaned the front two main grounds (G101 and 102) late last summer, but no help.

Driving me nuts. Hoping for some insight.

Thx
Mark

mmg

Guys I know this is a tired subject, but I really could use some help here please.

Smoken1

I would Clear all the Codes take it for a drive. Then Pull the codes B/4 you shut the car off
I attached a pdf file for you

mmg

Thanks very much guys for your help and input. I don't remember seeing a RTD NO COMM message, but might have missed it perhaps. Also strange to me that nothing that I listed are related to the issue. I plan to drive the car this afternoon and will do all that is suggested. Thank you again. Stay tuned.

Mark

mmg

I did the drive after clearing the codes, and ran diagnostics before shutting down car. Got most of the same as before:

10 PCM
P0480 HC
P1571 H
P1652 H
P1689 H

28 TCS
C1277 H


40 BCM
B0432 HC

58 SDM
U1040 H

A6 SCM
B2605 H
B2606 H
B2607 H

Also, I had the car stopped and restarted a few times after I took these codes. All codes remained the same, however there was one stop/start where the SERVICE TRACTION SYSTEM / SERVICE VEHICLE SOON / SERVICE ACTIVE HANDLING notices came on. But next start were gone. I have not done the battery load test yet. Need to take to a parts place tomorrow and have them do it. Does the battery have to be out of car?

Thx again,
Mark

mmg

I did not get the 80MPH limit message today. I'll check these links. Thanks. Mark

mmg

Had the battery load tested in the car this morning. Assuming the guy did it right (I was in the car starting it), he said the min voltage seen during the start was 10.96. I guess the battery is ok. I haven't had the max 80 etc messages come up today. But other codes are still present.

mmg

Ok, so I ran thru the ignition switch tests outlined by Bill Curlee and found that all the fuses were seeing voltage with the key in the "on" position. I did however notice that during the course of turning the key off and on a few times this morning that I did see the 28 TCS "no comm" and the 38 RTD "no comm" messages when I ran the diagnostics, along with SHOCKS INOPERABLE/Traction Control/80MPH messages come and go a few times. This just appears to be very intermittent, as you I'm sure guessed as well. Seems to be no real rhyme or reason.

My question now I guess is, even though all the fuses now currently show "ok" with the key in the on position (and no messages), could the ignition switch be intermittently working right with one start up and then not with another? If so, should I wait until I get all these messages and do the fuse check thing again per Bill's write up? I know the switch issues entail dirty or burned contacts...which to me could make these things work for one start and not for another?

Mark

Bill Curlee

YEP! Wont know for sure till you look!

mmg

Put a new battery in today (700 CCA) and the problem, so far, is worse than it was. Getting all the bad warnings now most times, plus no comm with TCS , RTD, and now for the first time HVAC. I even put a charger on the battery for an hour thinking it wasn't fully charged. I've restarted about 15 times and only once has it all cleared. Next start, same. Guess I'll do the ignition switch checks again.

mmg

Ok, I checked all the fuses on Bill's list pertaining to possible ignition switch failure. This was done while getting the warnings and "no comms" during the code checks prior to this test.

I found all fuses to be seeing voltage on both sides EXCEPT number 22 on the instrument panel fuse box. 22 is "BCM 13". No voltage on either side of this fuse.

This looks like an intermittent ignition switch problem to me based on this I think. I could probably wait until I get a "clean" start up and check this fuse again to confirm but I'm thinking I should just buy a new switch.

Any input or thoughts?

Thx
Mark

mmg

I'm going to have to buy a digital MM as mine is just an analog. Never be able to tell those small differences. Will check the door connectors as well. Thanks, Mark

mmg

I haven’t had a chance to check the door connectors yet, but got a digital MM and checked the fuses again. More weirdness I’m thinking.

I started out recording battery voltage. It was 12.08.
I then check all the underhood fuses that Bill said to check for ignition switch diagnosis.
19 – 12.05
18 – 12.05
17 – 12.05
22 – 12.01
16 – 12.01
13 – 12.01

I then did the instrument panel fuses
21 – 11.70
22 – 11.70 (Yes, this time it’s showing voltage…last check it was zero)
19 – 11.93.

I then checked the battery voltage again, as it had been about 10 minutes since I initially checked. It was 12.00. It should also be noted that while I was checking the 22 or 21 fuse, the HVAC control head came back on along with the HVAC interior fan. Cycling the key off and on after the testing showed that the HVAC control head was “out” again.
I’ll check the door to A piller connectors next, but this is the new info so far on the ignition switch diagnostics via fuse voltages.
Mark

mmg

I'll check it with neg post disconnected but it's a new battery I just bought two days ago.

mmg

I drove the car around for about 15 miles. The TC light etc was off after I drove the first mile or so. After about 10 miles, I stopped and restarted the car and the lights and messages came on and stayed on again the balance of the drive. I came home and checked the battery voltage. 12.95. I started the car again, all warnings remained on. I then took the off the boot around the wires that feed from the A pillar to the drivers side door. I could not pull enough of the wires out of the door to find the connectors, but did wiggle and move the bundle of wires around a bit and then reinstalled the boot. After that, I restarted the car 3 times and got no messages or TC light. Not sure if that's just luck or coincidence or what. I plan to let the vette sit overnight and then check the battery voltage again before I start it to see if it's draining down for some reason. Then, either way, I'll start it about 5 times and see if I get the warnings or if they remain out.

Can I get to those door connectors by removing the door panel if I wanted to do that?

Mark

mmg

Voltage this morning at the battery (hooked up, same as yesterday last time read) was 12.66. Down a bit from yesterday's 12.95. Started the car 5 times. All the bad messages are back every time and there's no comm from 28, 38 and HVAC. I shook the rubber door boot a number of times and also found the wires/connectors that go thru under the dash. I didn't try to separate the black connector, just moved everything around and jiggled the bundle. No change.

mmg

Well, I'm wondering what to do here next. I pulled both black connectors out of both door boots and looked at them separated. Nothing unusual. Scraped the connectors anyway and reinstalled. Shook the h*ll out of the boots as well. No changes to warnings...which are again SHOCKS INOPERATIVE, MAX SPEED 80 MPH, SERVICE RIDE CONTROL, SERVICE VEHICLE SOON.

Battery this morning was 12.6, so no real change from yesterday. I also did the fuse readings to look at ignition switch issues and everything was seeing voltage and wasn't very far off from battery voltage.

Here is the latest codes I collected after all this.

10 PCM
P0480 HC
P1133 C
P1153 C
P1571 HC
P1652 HC
P1689 HC

28 TCS No Comm
38 RTD No Comm

40 BCM
B0432 HC

58 SDM
U1040 HC

60 IPC
U1040 H

99 HVAC No Comm


Any ideas on what else to do here 8Vette7 and/or Bill C?

Thx for your patience and help.

Mark

mmg

Ok, I disconnected the smaller star connector and drove the car. The windows don’t work now as you said, but the seats DO. Not sure what that might mean.

Anyway, all the bad messages *were* gone after doing approx. 10 starts. Then, I went out to the car again about 5 minutes later to clear the codes and give you what I have now and I got the messages again…. Sometimes ABS, sometimes not. Always traction control. Here are my codes now:

10 PCM
P0480 C
P1571 HC
28 TCS – No comm

40 BCM
B0432 HC
58 SDM
U1040 HC
No comms from a lot of the remaining

The aluminum box has no oxidation or corrosion stains. No hints of water or previous water.
Mark

Bill Curlee

There are NUMEROUS other things to consider.. Post all you have..

BC

mmg

Sorry...

The 80 MPH did not come back on.

Here they all are:

10 PCM
P0480 C
P1571 H

28 TCS – No comm
38 RTD - No comm

40 BCM
B0432 HC

58 SDM
U1040 HC

99 HVAC - No Comm
A0 - LDCM No Comm
A1 - RDCM No Comm
A6 - SCM No Comm

TCS and Anti Lock panel lights remain lit. I also measured the battery output before I did all this again and it was 12.61.

Thanks again, Mark