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Hey all...really need some help diagnosing a slew of codes I got. Brief history of the car:
2001 Z06, I'm having a persistent issue with the ABS/Active Handling/Traction Control tripping out - no real rhyme or reason to when it trips, can be 5 min into drive or 30 min into drive. I've been thinking the EBTCM and/or wheel speed sensors. However over the last 3 days I cleared all codes and drove. Below is the list of codes I got on first test drive then a 15 min drive later this morning.
28-TCB C1288 HC
58-SDM B0026 HC
58-SDM U1016 H
58-SDM U1040 H
58-SDM U1096 H
58-SDM U1064 H
60-IFC B0521 H
AO-LDCM B2252 H
AO-LDCM B2282 H
AO-LDCM B2284 H
AO-LDCM B2262 H
AO-LDCM B2264 H
AO-LDCM U1255 H
AO-LDCM U1064 H
AO-LDCM U1016 H
AO-LDCM U1096 H
A1-RDCM B2283 H
A1-RDCM B2285 H
A1-RDCM B2265 H
A1-RDCM U1255 H
A1-RDCM U1064 H
A1-RDCM U1016 H
A1-RDCM U1096 H
As I've gone through the codes I'm not so sure I've been chasing the right areas. I have Sparco seats in the car and also an aftermarket Renown steering wheel. There is a good +/- 1" of play on the steering wheel in the center. Had David Farmer corner balancing the car over last couple days and he indicated the play is in the rack...would that cause the TC/AH to go off?
Second thing is the right/left control modules with horiz/vert position sensors...could that be cause?
Third, ABS is not working even before it throws current codes...right front wheel will lock
Then I found a thread about battery dying and causing all kinds of issues with the electronics...well, I have I have codes for Batt Circ 1 & 2 and loss of comms to a few different control modules and a tach circ malfunction (??).
I'm at a complete loss on this and could really use some help diagnosing what is going on. The low battery thing seems to hold the most weight in that it is a bunch of kind of random things, but the steering and position sensors make sense with the interior changes, but doesn't really address the ABS. Appreciate any help/insight you guys can offer...thanks in advance!!
The LDCM and RDCM codes indicate you had voltage level issues in the doors. Those codes are history codes. That usually means the battery was low and once recharged the failures went from current to history. If you have a continuing voltage problem that could also reflect into issues with the EBCM. You may need to check all of the power connections and ground connections involved with the EBCM to make sure they are clean and corrosion free.
The C1288 code indicates a problem with the steering sensor and one of the first things to check is to make sure the alignment is set so the car isn't pulling one way or another or the steering wheel isn't off center by too much. A constant off center even though the car is going straight can cause this code to get thrown.
You say the right front wheel is locking up which means the ABS isn't working but I don't see any codes involving the ABS. The steering sensor isn't required for ABS functionality so C1288 should not deactivate the ABS. With that code you should see Service Active Handling message. Not ABS. Are you sure the wheel is locking up or are you getting some random activation of the Active Handling (application of right front brake) just before the code deactivates the function?
Another thing that could be wrong is there could be an issue with the steering wheel air bag clock spring. I know you have an aftermarket wheel which doesn't have an air bag so you would expect to get the B0026 code due to the subsequent open circuit. However, both the clock spring and the steering sensor can be ruined if the steering shaft was disconnected from the rack while the car was being worked on and the steering shaft was subsequently turned more than one turn. Just something to think about. Slop in the rack or maybe the steering shaft was turned to many degrees.
The LDCM and RDCM codes indicate you had voltage level issues in the doors. Those codes are history codes. That usually means the battery was low and once recharged the failures went from current to history. If you have a continuing voltage problem that could also reflect into issues with the EBCM. You may need to check all of the power connections and ground connections involved with the EBCM to make sure they are clean and corrosion free.
The C1288 code indicates a problem with the steering sensor and one of the first things to check is to make sure the alignment is set so the car isn't pulling one way or another or the steering wheel isn't off center by too much. A constant off center even though the car is going straight can cause this code to get thrown.
You say the right front wheel is locking up which means the ABS isn't working but I don't see any codes involving the ABS. The steering sensor isn't required for ABS functionality so C1288 should not deactivate the ABS. With that code you should see Service Active Handling message. Not ABS. Are you sure the wheel is locking up or are you getting some random activation of the Active Handling (application of right front brake) just before the code deactivates the function?
Another thing that could be wrong is there could be an issue with the steering wheel air bag clock spring. I know you have an aftermarket wheel which doesn't have an air bag so you would expect to get the B0026 code due to the subsequent open circuit. However, both the clock spring and the steering sensor can be ruined if the steering shaft was disconnected from the rack while the car was being worked on and the steering shaft was subsequently turned more than one turn. Just something to think about. Slop in the rack or maybe the steering shaft was turned to many degrees.
Bill
Bill, thank you! That is great information...I'll go through all the grounds and connections, I do have some slop in the steering that appears to be in the rack (it isn't at the steering column junction). Is there a way to tighten up the rack at all to eliminate that slop or does the rack need to be replaced? I'm skeptical that the steering got disconnected and turned, but it isn't impossible - any way to know which way it might have gotten spun so I don't inadvertantly spin it the wrong way again (definitely breaking that clock spring and sensor)? I'm not thinking there is, but figured I'd ask.
You have to correct the voltage issues before you go any further. Once that is resolved,,, THEN we can address any issues that are remaining.
YES, the grounds are important. So are the battery feeds that go to each module. What does the DC Volt meter on the IPC and the DIC volt meter read when you are having issues??? REMEMBER,,,, The Volt meter/s inside the car DOES NOT indicate the status of your charging system. It tells you what voltage is coming out of the IGNITION SWITCH.
Several things can cause module voltage (hot in run and start) to be LOW. One is a worn out dirty/burnt ignition switch! almost all of the modules have TWO battery power supplies. One comes directly from the battery always HOT buss. The other (Hot in Run /Crank) comes out of the ignition switch and tells the module to wake up and function.
If the voltage on the (Hot in Run and Crank/start) is low or deficient, it can and will cause the issues you are seeing.
You can actually measure that voltage on the fuses that are supplied by that Hot in Run and Start/crank) buss. On top of each FUSE are two small test slots. Measure each test slot to chassis ground. You SHOULD read full battery voltage on each slot to ground when the ignition switch is ON.
If the voltage is a lot lower than actual battery voltage (measured at the battery terminals) that ignition switch needs changed.
Excellent information! Okay, the DC volt meter in the car reads 11.2 volts. When measured on the battery (terminal to terminal) I get 12.2v. So, moving to the Fuse (#19 if I'm reading correctly) I get 11.2v across one terminal and 11.7v across the other when the ignition switch is ON.
Is that enough of a difference to indicate the ignition switch is going bad?
With key ON if you are reading 12.2 volts at the battery and getting 11.7 and 11.2 ( my IGN1 fuse 19 reads the same across the fuse) you have a a .5 and a 1.0 voltage drop across the switch...it’s EXCESSIVE !!...I’m lucky if I read .02-.03 volts max !!....I prefer reading directly from battery positive to whatever fuse you are checking...no math involved...just read the voltage drop directly !!
Wow...thanks guys, guess it looks like I'm pulling the ignition switch. I'll finish cleaning all the grounds and pull the ignition. Sounds like I'm going to find some burned contacts. Been reading the whole switch repair threads so doesn't look to be a complex fix, just hoping I wouldn't have to go there.
I'll get that cleaned up and run the car a little, then post back if anything re-emerges.
JUST A NOTE.. I started the Ignition Switch cleaning process. I was trying to save the C5 owner a little cash. I am pretty savvy at doing complex and integrate work and have a pretty good understanding on basic electronics/electricity. When you get done cleaning, adjusting the tension on the switch contact arms, polishing the contact points, making sure that the contacts are absolutely parallel,,, ect,, You MUST use an OHM METER and make absolutely sure that the switch is actually making the correct zero ohm contact between ALL of the switch contacts each and every time you operate the switch.
There have been quite a few people who for what ever reason DONT get the overhaul procedure / process right and the switch fails to preform. For some, just purchasing a NEW switch is the best option..
Yes, understood. I feel pretty confident to do the all the process, but do you by any chance maybe have a picture of what terminals to verify on the switch afterwards? Just a visual to insure I test across the switch on the right places? The testing doesn't bother me, just not as confident I know specifically which terminals to test.
*EDIT* Never mind Bill, I found your hand drawn schematic in the repair thread.
Having said that...is it possible to change the key cylinder from the old switch to the new? If so, is there a trick to removing the cylinder? A new switch is +/- $70 and I'm not opposed to just putting in a new one (I'm second owner of car and in the process of getting everything where I know it should be, kind of baselining the major components), but would prefer to not have to re-key if I can get away with it.
Last edited by darthwader; 03-12-2019 at 02:34 PM.
First off I would list the details of your C5 in your profile...year, trans, mods,etc !!...sometimes there ARE variances in wiring from one model year to the next. You change out the old cylinder to the new...plug and play !!...this is out of my 01's FSM.
Gentlemen,
Wanted to give a quick follow up and update - cleaned all the grounds in the engine thoroughly and the car is back to normal! No codes after a few drives, even had to go through "Active Handling warming up" this morning and it was a bit chilly driving in, but it cycled through fine and all the electronics seems to be stable. I wound up purchasing a new ignition, but haven't installed as the grounds seem to have corrected. Will hold onto it for a few more days just in case, but it is looking like I had ground issues.
Showing +/- 13.6v on the IPC when car is on and will have to check again with key in ACC to see what the battery is putting out. Still watching/assessing, but wanted to pass along progress and say another thank you to everyone. Your help is invaluable and while a lot of these topics have been discussed in the past, for those of us new to the C5's your knowledge and willingness to share that knowledge is incredibly helpful - so thank you.
Hi Guys,
Well, so far all has been good, but I did get another code pop up this morning...TC1287. I had TC1288 come on as I went through a car wash (underside blast) but it cleared on ignition cycle and hadn't come back until today, well similar code today.
Question for you guys, done some searching and digging and found a post from Bill Dearborn that sounds like it might be on point (link below):
However, in the discussion it talks about a lack of voltage can also cause this to go into error. I think I have found a write up on how to test the steering sensor based off an 02 Z06, but should that be the same for an 01?
I don't seem to be seeing any other voltage issues since cleaning all the grounds, but do have a new ignition I could put in. Guess wondering if you guys have any thoughts on what would be best next step? I'm inclined to look at the steering sensor to see if it is compromised before jumping on the ignition...does that sound reasonable or do I need to give more information to assess next steps?
Hi Guys,
Well, so far all has been good, but I did get another code pop up this morning...TC1287. I had TC1288 come on as I went through a car wash (underside blast) but it cleared on ignition cycle and hadn't come back until today, well similar code today.
Question for you guys, done some searching and digging and found a post from Bill Dearborn that sounds like it might be on point (link below):
However, in the discussion it talks about a lack of voltage can also cause this to go into error. I think I have found a write up on how to test the steering sensor based off an 02 Z06, but should that be the same for an 01?
I don't seem to be seeing any other voltage issues since cleaning all the grounds, but do have a new ignition I could put in. Guess wondering if you guys have any thoughts on what would be best next step? I'm inclined to look at the steering sensor to see if it is compromised before jumping on the ignition...does that sound reasonable or do I need to give more information to assess next steps?
Thanks guys, really appreciate all your help!!
Wow, a post from 12 years ago. I still had my 03 then. In your first posts you mentioned there was some play in the steering and David Farmer told you it was in the rack. That play may be causing your issue.
• During diagnosis, park the vehicle on a level surface.
• Check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface. If you have the steering wheel turned to one side while driving straight or are moving it back and forth to keep the car straight that could cause a problem. If you have as much play in the steering as you indicate the AH system may be seeing that as a steering input.
You also mentioned after you got the rest of the DTCs to go away that you had an issue with Active Handling Warming Up. That is caused when the car can't readily determine where straight ahead is just after an engine start. When you turn off the ignition the AH straight ahead calibration goes away. Then when you restart the engine and start the car moving the system has to determine where straight ahead is in the first few feet of travel. It needs all wheel speed sensors reporting the speeds they would report when moving straight ahead (when turning they report different speeds) and then the system sets the readings it sees coming from the steering sensor as straight ahead. The system does this when the vehicle reaches about 6 mph and it can take a few hundred feet before it is ready. If you turn the steering wheel before that time period is up then you get the warming up message and the system waits until you are going straight ahead again. I used to get this all the time when I was autocrossing if I wanted to use Competition Mode for instance if it was raining. When it was close to my turn at the starting line I would drive the car to the far end of the lot and drive back in a straight line so AH was calibrated before I got to the starting line. That way I didn't get the warming up message in the middle of a run.
To get rid of your C1287 abd 1288 codes you may need to resolve the play in the steering rack.
Bill
Last edited by Bill Dearborn; 03-23-2019 at 09:52 PM.
Thanks Bill...it might well be the slop in the steering, but read on as it gets more interesting. As an aside, alignment should be good - David F did it and corner balanced the car for me so the set up should be spot on, he's a pretty smart guy. ;-) The car does track pretty straight, David fixed a horrible toe issue and I just got new front tires on yesterday so will need to test the 'rolling straight' again with new shoes.
I'll keep searching to see if there are any remedies aside from replacing the R&P, but my hopes are low. At end of the day it isn't a big issue as I'm only concerned about retaining the ABS....which leads to the next part.
...got the 1287 code again, what triggered this time was actually a brake test (new SS lines and a flush), checking them out and hopped on the brakes to feel them...ABS activated (got the dash notice) and right front tire squeeled (locked up momentarily). Right after that is when the code came on. Could I be chasing the wrong thing here...maybe the right front wheel speed sensor? Or the ABS system? I'm not getting any of the EBCM codes, but the lock on that front right is possibly what caused the whole code since it is measuring wheel speed delta (that's right isn't it?). Makes me wonder about wheel speed sensors because I got it last time with the under blast of a car wash...
Last edited by darthwader; 03-25-2019 at 04:58 PM.
I would find a good clean level road where it is SAFE to do some serious 60-0 Stops and see if you still get the wheel lock up. Could have been a fluke.
03-09-2019, 01:41 PM
Diagnostic help - Slew of codes
As an aside, alignment should be good - David F did it and corner balanced the car for me so the set up should be spot on, he's a pretty smart guy. ;-) The car does track pretty straight, David fixed a horrible toe issue and I just got new front tires on yesterday so will need to test the 'rolling straight' again with new shoes.