"Trac Off" light won't go off - 2000 Grand Am.

[mrsilv04]

My niece just called me. She says her "Trac Off" (Electronic Traction Control) light is lit on her instrument panel.

I told her to press the traction control button on the dash, she said it didn't change anything.

5 miles before the "Trac Off" light came on, she was driving on a really low tire (which has been pumped up - tire has a slow leak).

Is the low tire and the "Trac Off" light a coincidence? I guess I'll jump in the truck and head to where she works and have a look-see for myself.

 

[chevrofreak]

I bet the car disabled the traction control when it detected that one of the 4 wheels was traveling at a different speed than the others.

 

[dwcopple]

wheel speed sensor...common

 

[PT1]

Originally Posted By: dwcopple
wheel speed sensor...common


+1 the wheel speed sensors need cleaning or replacement.

 

[chevrofreak]

I say disconnect the battery or clear the codes with a reader before you replace anything. See if it comes back.

 

[mrsilv04]

Originally Posted By: chevrofreak
I say disconnect the battery or clear the codes with a reader before you replace anything. See if it comes back.


That's going to be my next move. It seems to be too much of a coincidence that this happened right after she was driving on a low tire.

 

[XCELERATIONRULES]

Originally Posted By: PT1
Originally Posted By: dwcopple
wheel speed sensor...common


+1 the wheel speed sensors need cleaning or replacement.


+2
I already replaced the abs wheel sensors a couple times on my buddies car.
If abs equipped the abs light should be on also.

 

[GMBoy]

Why guess? Here you go: (sorry the cut and paste isn't the best!) No mention of wheel speed sensors as a possible problem


Service Information
2000 Pontiac Grand Am | Alero, Grand Am (VIN N) Service Manual | Brakes | Antilock Brake System | Diagnostic Information and Procedures | Document ID: 649963
--------------------------------------------------------------------------------

Low Traction Indicator Always On




Circuit Description
Four-way serial communication is sent back and forth between the EBCM, IPC, PCM, and the BCM. A message from the IPC is sent to the BCM within seven seconds after ABS initialization. A serial communication failure does not allow the proper warning indicator commands to be sent back to the IPC.

Diagnostic Aids
Use the Lamp Test function of the Scan Tool in order to turn the indicator ON and OFF while looking for an intermittent malfunction.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

• Backed out terminals

• Improper mating

• Broken locks

• Improperly formed or damaged terminals

• Poor terminal-to-wiring connections

• Physical damage to the wiring harness

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This test ensures that the instrument cluster can operate the LOW TRAC indicator.

Step
Action
Value(s)
Yes
No

1
Did you perform the ABS Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - ABS

2
Turn OFF the ignition.
Install a scan tool.
Turn ON the ignition, with the engine OFF.
Select the Body menu and then IPC on the scan tool.
Select Lamp Test on the scan tool.
With the scan tool, turn the warning indicators ON and OFF
Does the LOW TRAC indicator turn ON and OFF?
--
Go to Step 3
Go to Step 4

3
Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 7
Go to Step 5

4
Inspect for poor connections at the harness connector of the instrument cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 7
Go to Step 6

5
Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the repair?
--
Go to Step 7
--

6
Replace the instrument cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Did you complete the repair?
--
Go to Step 7
--

7
Operate the system in order to verify the repair.

Did you correct the condition?
--
System OK
Go to Step 2

© 2008 General Motors Corporation. All rights reserved.

 

[GMBoy]

I'm sorry - disregard the above -thats for the low traction light. You were refering to the trac off light.

You'll need a Tech 2. I would try to jump the trac switch to see if the switch is bad because that is the cheapest cause listed.

Here you go:



Service Information
2000 Pontiac Grand Am | Alero, Grand Am (VIN N) Service Manual | Brakes | Antilock Brake System | Diagnostic Information and Procedures | Document ID: 578370
--------------------------------------------------------------------------------

ETS Off Indicator Always On




Circuit Description
Four-way serial communication is sent back and forth between the EBCM, IPC, PCM, and the BCM. A message from the IPC is sent to the BCM within seven seconds after ABS initialization. A serial communication failure does not allow the proper warning indicator commands to be sent back to the IPC.

Diagnostic Aids
The ETS OFF indicator will be ON and the Enhanced Traction System will be disabled whenever the scan tool is connected to the DLC with the ignition switch is in the ON position.

Use the Lamp Test function of the Scan Tool in order to turn the indicator ON while looking for an intermittent malfunction in the ETS OFF warning indicator circuitry.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

• Backed out terminals

• Improper mating

• Broken locks

• Improperly formed or damaged terminals

• Poor terminal-to-wiring connections

• Physical damage to the wiring harness

Test Description
This test determines if a Powertrain malfunction has turned the ETS Off indicator ON.

This test determines if the malfunction is caused by the IPC.

This test checks for an ETS Off switch stuck in the closed position.

This test checks for a short to ground in the switched input to the BCM.

Step
Action
Value(s)
Yes
No

Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual.

1
Was the ABS Diagnostic System Check performed?
--
Go to Step 2
Go to Diagnostic System Check - ABS

2
Turn the ignition switch to the OFF position.
Connect a Scan Tool .
Turn the ignition switch to the ON position.
Use the Scan Tool in order to check for any PCM DTCs.
Are there any PCM DTCs?
--
Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 2.4L or Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.4L
Go to Step 3

3
Use the Scan Tool to select the BODY Menu.
Use the Scan Tool to select IPC then Lamp Test.
Use the Scan Tool to turn the warning indicators OFF.
Did the warning indicators turn OFF?
--
Go to Step 4
Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gages and Console

4
Disconnect the ETS Off switch connector.

Does the ETS Off indicator turn OFF?
--
Go to Step 7
Go to Step 5

5
Disconnect the BCM connector C3.
Using the J 39200 measure the resistance between the ETS Off switch harness connector terminal A and ground.
Is the resistance within the specified range?
OL

(Infinite)
Go to Step 6
Go to Step 8

6
Turn the ignition switch to the OFF position.
Inspect the following components:
• The BCM connector C3

• The ETS Off connector

Inspect the above components for the following conditions:
• Damage

• Poor terminal contact

• Terminal corrosion

Are there signs of poor terminal contact, corrosion or damaged terminals?
--
Go to Step 9
Go to Step 10

7
Replace the ETS Off switch.

Is the repair complete?
--
Go to Diagnostic System Check - ABS
--

8
Repair short to ground in CKT 1571.

Is the repair complete?
--
Go to Diagnostic System Check - ABS
--

9
Replace all of the terminals or connectors that exhibit signs of poor terminal contact, corrosion or damaged terminal(s).

Is the repair complete?
--
Go to Diagnostic System Check - ABS
--

10
Replace the BCM.

Is the repair complete?
--
Go to Diagnostic System Check - ABS
--

© 2008 General Motors Corporation. All rights reserved.

 

[mrsilv04]

Originally Posted By: XCELERATIONRULES
Originally Posted By: PT1
Originally Posted By: dwcopple
wheel speed sensor...common


+1 the wheel speed sensors need cleaning or replacement.


+2
I already replaced the abs wheel sensors a couple times on my buddies car.
If abs equipped the abs light should be on also.


No ABS light...

 

[mrsilv04]

Disconnecting the battery cable cleared the light.

I suspect the problem was the low tire. Since the revs per mile on one wheel were different for something more than a few seconds, it threw a code, shut down the traction control, and lit the light on the dash.

Hopefully, the low tire is a thing of the past. Put a new set of Traction T/A's on it last night.