Content .. 758 759 760 761 ..

Hummer H2. Manual - part 760

Test Description

The number below refers to the step number on the diagnostic table.

4: This step tests for voltage on the TC2 mode switch signal circuit indicating an unpressed TC2 mode
switch.

5: This step tests for voltage on the TC2 mode switch signal circuit indicating a pressed TC2 mode
switch.

DTC B3626

Step

Action

Values Yes

Schematic Reference: ABS Schematics
Connector End View Reference:ABS Connector End Views

Did you perform the ABS Diagnostic System Check?

Go to

Step 2

Go to

Diagnostic

System Check -

ABS

1. Use a scan tool in order to clear the DTCs.

2. Turn OFF the ignition for 5 seconds.

3. Start the engine.

4. Observe the scan tool for up to 60 seconds in order to

verify the DTC resets.

Does the DTC set?

Go to

Step 3

Go to Diagnostic

Aids

1. Turn OFF the ignition.

2. Disconnect the TC2 mode switch harness connector.

3. Turn ON the ignition.

4. Connect a test lamp between the IGN 1 voltage circuit,

IGN E fuse, and a good ground.

Does the test lamp illuminate?

Go to

Step 4

Go to Step 11

1. Turn OFF the ignition.

2. Reconnect the TC2 mode switch harness connector.

3. Turn ON the ignition.

4. Backprobe the TC2 mode switch harness connector in

order to connect a DMM between the TC2 mode switch
signal circuit and a good ground. Refer to Probing
Electrical Connectors in Wiring Systems.

5. Measure the DC voltage on the TC2 mode switch signal

circuit.

Does the TC2 mode switch signal measure with in the specified

12 V

Go to

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

range?

Step 5

Go to Step 6

1. Press and hold the TC2 mode switch.

2. Use a DMM in order to measure the DC voltage on the

TC2 mode switch signal circuit.

Does the TC2 mode switch signal measure within the specified
range?

0.5 V

Go to

Step 7

Go to Step 13

Test the TC2 mode switch signal circuit for a short to ground.
Refer to Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to

Step

Go to Step 12

1. Turn OFF the ignition.

2. Disconnect the wiring harness connector from the EBCM.

3. Connect the J 39700 universal pinout box using the. See

Special Tools and Equipment . J 39700-530 cable adapter
to the EBCM harness connector only.

4. Turn ON the ignition.

5. Use a DMM in order to measure the DC voltage on the

TC2 mode switch signal circuit.

Does the TC2 mode switch signal measure within the specified
range?

12 V

Go to

Step 9

Go to Step 8

Repair the open in the TC2 mode switch signal circuit. Refer to
Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to

Step

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

Go to Step 10

Replace the EBCM. Refer to Electronic Brake Control Module
Replacement .
Did you complete the replacement?

Go to

Step

Repair the open or short to ground in the IGN 1 voltage circuit,
IGN E fuse. Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you complete the repair?

Go to

Step

Inspect for open in the TC2 switch ground circuit or poor
connections at the harness connector of the TC2 mode switch.
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

Go to Step 13

Replace the TC2 mode switch. Refer to Traction Control
Switch Replacement
Did you complete the replacement?

Go to

Step

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

DTC C0035-C0051

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

C0035 C0040 C0045 C0050

The ignition is ON.

C0036 C0041 C0046 C0051

Vehicle speed is over 40 km/h (25 mph).

The brake pedal is not pressed.

The ABS is not active.

Conditions for Setting the DTC

C0035 C0040 C0045 C0050

One of the following conditions exists for 0.02 seconds:

A short to voltage in the wheel speed sensor signal circuit.

An open in the wheel speed sensor signal circuit.

C0036 C0041 C0046 C0051

All of the following conditions exists for 0.01 seconds:

The suspect wheel speed equals zero.

The other wheel speeds are greater than 40 km/h (25 mph) for 0.01 seconds.

The suspect wheel equals zero during drive off, and the other wheels are greater than 18 km/h (11 mph).

A short to ground the wheel speed sensor signal circuit is shorted to ground.

A deviation of 2 wheel speeds at either side of the vehicle greater than 6 km/h (4 mph), or at the front
axle greater than 10 km/h (6 mph) for a time period of 10 to 20 seconds.

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for Running the

DTC as specified in the supporting text.

Does the DTC reset?

Go to

Step 3

System OK

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

Action Taken When the DTC Sets

If equipped, the following actions occur:

The electronic brake control module (EBCM) disables the anti-lock brake system (ABS)/traction control
system (TCS) for the duration of the ignition cycle.

A DTC malfunction will set.

The ABS indicator turns ON.

The Red BRAKE Warning indicator could turn ON.

Conditions for Clearing the DTC

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

The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC
is not detected in 100 consecutive drive cycles.

Diagnostic Aids

C0035 C0040 C0045 C0050

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:

1. Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater solution, add

2 teaspoons of salt to 354 ml (12 oz) of water.

2. Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 40 km/h (25 mph) for at least

30 seconds.

3. If the DTC returns, replace the suspected wheel speed sensor or repair the wheel speed sensor wiring.

4. Rinse the are thoroughly when completed.

C0036 C0041 C0046 C0051

Under the following conditions, 2 Wheel Speed Sensor Input is 0 DTCs are set:

The 2 suspect wheel speeds equal zero for 10-20 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.

C0036 C0041 C0046 C0051

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

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

Content .. 758 759 760 761 ..