Hi-

I'm new to Vette's, just bought a 02 zo6.

I have a c1232 code and 2 warning lights on the dash.

I did lots of reading on this site and checked the harness on the left side at the junction at the frame then at the connector that plugs in to the ebcm. I have the same ohm reading at the hub as I do at the ebcm connector. The reading is where it should be per a thread a read on the site.

I don't know what else could be wrong other than the ebcm being the problem.

Any advice would be greatly appreciated.

Mike

 

Bad ABS wheel sensor Left Front wheel?

C1232 through C1235
One of the following conditions exists for 0.02 seconds:

A short to voltage - the wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both greater than 4.25 volts.
A short to ground - the wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both less than 0.75 volts.
An open - the wheel speed sensor signal circuit voltage is greater than 4.25 volts and wheel speed sensor return circuit voltage is less than 0.75 volts.

 

A bad wheel bearing is a possibility. You can spin the wheel and see if you can read an AC voltage equal to or greater than 100 mv at the wheel speed sensor connector. If you get a voltage swap the wheel bearing with the right front and see if you get a different code (C1233). If the code doesn't move the EBCM could be at fault.

Bill

 

I got a voltage when i spun the wheel, it varied though as I rotated the rotor, which I thought was normal, maybe not I guess?

 

I forgot to add that the car has only 4000 miles on it, it's one reason I'm not convinced there is an issue with the hub but I don't know these cars, this is my 1st one.

 

Varied as it when up and down or it was higher at some points then others?

 

as i moved the rotor it go up and then drop as it slowed, it wasn't consistent, i wasn't moving it consistently either. could prob try again with tire on.

 

ok. I lifted the wheel and spun it consistantly and the voltage varied between 250mv to 280mv. so to check, I found the pins for the right side and that measured the same resistance and when I spun the tire, it measured approx the same. After cking both, I'm assuming the sensor is ok. and maybe it's the ebcm? what do you think?

 

I've been through the same process with the 1233 (RF sensor) code. I'm also getting a 1283 (Excessive time to center steering) which after troubleshooting is pointing towards the EBCM as well. I don't think the issues with the wheel sensors and the aditional 1283 code is going to "not" allow us the cheep fix by abfixer (which is just a relay fix). I think a new board is in order. Will be interesting to see if anyone responds with a "nice" fix.

 

i'm hoping for a fix post but i think buying a used or refurbished ebcm is the answer. after checking both front wheels i don't know what else it can be.

 

3
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Disconnect the wheel speed sensor connector.
Measure the resistance across the wheel speed sensor.
Does the resistance measure within the specified range?
850-1350 ohms
Go to Step 4
Go to Step 8

4
Spin the wheel.
Measure the AC voltage across the wheel speed sensor.
Does the AC voltage measure greater than the specified value?
100 mV
Go to Step 5
Go to Step 8

 

DTC C1221-C1235
Circuit Description
As the wheel spins, the wheel speed sensor produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.

Conditions for Running the DTC
C1221 through C1228
• DTCs C1232 through C1235 are not set.

• The brake pedal is not pressed.

• The ABS is not active.

C1232 through C1235
The ignition is ON.

Conditions for Setting the DTC
C1221 through C1224
All of the following conditions exists for 2.5 seconds:

• The suspect wheel speed equals zero.

• The other wheel speeds are greater than 8 km/h (5 mph).

• The other wheel speeds are within 11 km/h (7 mph) of each other.

C1225 through C1228
The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 16 km/h (10 mph) or more in 0.01 second. The change must occur 3 times with no more than 0.2 seconds between occurrences.

C1232 through C1235
One of the following conditions exists for 0.02 seconds:

• A short to voltage - the wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both greater than 4.25 volts.

• A short to ground - the wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both less than 0.75 volts.

• An open - the wheel speed sensor signal circuit voltage is greater than 4.25 volts and wheel speed sensor return circuit voltage is less than 0.75 volts.

Action Taken When the DTC Sets
If equipped, the following actions occur:

• The EBCM disables the ABS/TCS/VSES for the duration of the ignition cycle.

• The DRP does not function optimally.

• The ABS indicator turns ON.

• The Traction Control and Active Handling indicator turns ON.

• The DIC displays the following messages:

- Service ABS

- Service Traction System

- Service Active Handling

Conditions for Clearing the DTC
• The condition for the DTC is no longer present and the DTC is cleared with a scan tool.

• The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids
C1221 through C1224
Under the following conditions, 2 Wheel Speed Sensor Input is 0 DTCs are set:

• The 2 suspect wheel speeds equal zero for 60 seconds.

• The other wheel speeds are greater than 16 km/h (10 mph).

• The other wheel speeds are within 11 km/h (7 mph) of each other.

Diagnose each wheel speed sensor individually.

C1225 through C1228
A possible cause of this DTC is electrical noise on the wheel speed sensor harness wiring. Electrical noise could result from the wheel speed sensor wires being routed to close to high energy ignition system components, such as spark plug wires.

C1232 through C1235
If the customer comments that the ABS indicator is ON only during moist environmental conditions (rain, snow, vehicle wash, etc.), inspect the wheel speed sensor wiring for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:

Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater solution, add 2 teaspoons (9.9 ml) of salt to 354 ml (12 oz) of water.
Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 40 km/h (25 mph) for at least 30 seconds.
If the DTC returns, replace the suspected wheel speed sensor or repair the wheel speed sensor wiring.
Rinse the area thoroughly when completed.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

Measure the resistance of the wheel speed sensor in order to determine if the sensor has a valid resistance value.

Ensures that the wheel speed sensor is generating a valid AC voltage output.

Step
Action
Values
Yes
No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

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

2
Install a scan tool.
Turn ON the ignition.
Set up the scan tool snap shot feature to trigger for this DTC.
Drive the vehicle at a speed greater than the specified value.
Does the scan tool indicate that this wheel speed DTC set?
8 km/h (5 mph)
Go to Step 3
Go to Diagnostic Aids

3
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Disconnect the wheel speed sensor connector.
Measure the resistance across the wheel speed sensor.
Does the resistance measure within the specified range?
850-1350 ohms
Go to Step 4
Go to Step 8

4
Spin the wheel.
Measure the AC voltage across the wheel speed sensor.
Does the AC voltage measure greater than the specified value?
100 mV
Go to Step 5
Go to Step 8

5
Inspect for poor connections at the harness connector of the wheel speed sensor. 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 10
Go to Step 6

6
Disconnect the EBCM harness connector.
Install the J 39700 universal pinout box using the J 39700-300 cable adapter to the EBCM harness connector only.
Test the wheel speed sensor circuits for the following:
• An open

• A short to ground

• A short to voltage

• Shorted together

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 10
Go to Step 7

7
Inspect for poor connections at the harness connector for 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 10
Go to Step 9

8
Replace the wheel speed sensor. Refer to Front Wheel Bearing and Hub Replacement in Front Suspension or Rear Wheel Bearing and Hub Replacement in Rear Suspension.

Did you complete the replacement?
--
Go to Step 10
--

9
Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the repair?
--
Go to Step 10
--

10
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
--
Go to Step 2
System OK

 

thanks for the posts, still trying to sort this out.