Hummer H2. Manual — part 764

DTC C0192

Circuit Description

The vehicle uses the longitudinal accelerometer input when calculating the desired traction control. The usable
output voltage range for the longitudinal accelerometer 0.48-4.84 volts. The scan tool will report zero
longitudinal acceleration as 2.5 volts with no sensor bias present.

The longitudinal accelerometer sensor bias compensates for sensor mounting alignment errors and electronic
signal errors.

Conditions for Running the DTC

z

The ignition is ON.

z

The vehicle speed is greater than 40 km/h (25 mph).

Conditions for Setting the DTC

z

If during stable driving conditions, the longitudinal accelerometer signal becomes larger than 0.26 g, the
EBCM controller will disregard the signal so that a false EBCM intervention is prevented. A malfunction
is detected if this condition continues for more than two seconds.

z

Under normal driving conditions, the long time filtered driving direction is straight ahead. The long time
filtered longitudinal accelerometer value is called the offset. If the offset value is higher than 0.23 g, a
malfunction is detected. Malfunction time depends on driving distance, vehicle speed and the amount of
malfunctioning longitudinal accelerometer signal.

z

The longitudinal accelerometer signal is limited to an electrical stop of 1.8 g. If the longitudinal
accelerometer signal is greater than 1.5 g for more than 500 milliseconds, a malfunction is detected.

z

At a standstill, the range of the longitudinal accelerometer signal is less than 0.7 g. If the longitudinal
accelerometer signal is greater than 0.7 g at standstill, a malfunction is detected.

z

longitudinal accelerometer signal cannot change rapidly under normal driving conditions. If the
longitudinal accelerometer signal is changing faster than 55 g per second, a malfunction is detected.

15

Replace the vehicle LNG accelerometer sensor. Refer to
Longitudinal Accelerometer Replacement .
Did you complete the replacement?

-

Go to Step

17

-

16

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

-

Go to Step

17

-

17

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 2

System OK

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

Action Taken When the DTC Sets

z

A malfunction DTC is set

z

TCS is disabled for the duration of the ignition cycle

z

ABS remains functional

z

ABS lamp indicators turn on

Conditions for Clearing the DTC

z

The condition for the DTC is no longer present

z

A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no
longer present.

z

Using a scan tool.

Diagnostic Aids

Any circuitry that is suspected of causing an intermittent complaint should be thoroughly checked for improper
mating, improperly formed or damaged terminals, poor terminal to wiring connections, or physical damage to
the wiring harness. If an intermittent condition exists, refer to Testing for Intermittent Conditions and Poor
Connections in Wiring Systems.

Test Description

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

2: Checks for specified voltage on the longitudinal accelerometer signal circuit.

3: Checks for specified 5-volt reference on the longitudinal accelerometer reference circuit.

DTC C0192

Step

Action

Value

(s)

Yes

No

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

1

Did you perform the ABS Diagnostic System Check?

-

Go to

Step 2

Go to Diagnostic

System Check -

ABS

2

1. Turn OFF the ignition.

2. Disconnect the EBCM connector.

3. Install the J 39700 universal pinout box with the. See

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

4. Turn the ignition ON, with the engine OFF.

2.3-2.7

V

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

DTC C0245

Circuit Description

The speed sensors used on the front of this vehicle are multiple pole and the rear uses a single pole magnetic
pickup. This sensor produces an AC signal that the EBCM uses the frequency from to calculate the wheel
speed.

Conditions for Running the DTC

z

The ignition switch is ON.

z

The DTC can be set after system initialization.

Conditions for Setting the DTC

z

The EBCM detects a deviation between two wheel speeds at either side of the vehicle greater than 6 km/h
(3.75 mph) at a vehicle speed of less than 100 km/h (62 mph).

z

The EBCM detects a deviation between the left and right front wheel speeds of greater than 10 km/h
(6.25 mph) at a vehicle speed of less than 100 km/h (62 mph).

5. Using the DMM, measure the voltage between pin 10

and pin 15 of the J 39700 universal pinout box. See
Special Tools and Equipment .

Is the voltage within the specified value?

Go to

Step 3

Go to Step 6

3

Using the DMM, measure the voltage between pin 28 and pin
15 of the J 39700 universal pinout box. See Special Tools and
Equipment .
Is the voltage within the specified value?

4.5-5

V

Go to

Step 4

Go to Step 6

4

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

2. Perform the Diagnostic Test Drive.

Does the DTC reset?

-

Go to

Step 5

Go to Diagnostic

Aids

5

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

-

Go to

Step 7

-

6

Replace the vehicle longitudinal accelerometer sensor. Refer to
Longitudinal Accelerometer Replacement .
Did you complete the repair?

-

Go to

Step 7

-

7

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 2

System OK

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

z

The EBCM detects a deviation between the left and right front wheel speeds of greater than 4 km/h (2.5
mph) plus 6 percent of the vehicle speed at greater than 100 km/h (62 mph).

This DTC will set when the EBCM cannot specifically identify which wheel speed sensor is causing the
malfunction. If the EBCM can identify the specific wheel speed sensor causing the malfunction, DTC C0245
will become a history DTC, and the DTC associated with the sensor DTC C0036, DTC C0041, DTC C0046,
DTC C0051, will be set concurrent with DTC C0245.

Action Taken When the DTC Sets

If equipped, the following actions occur:

z

The EBCM disables the ABS if the exact fault can be determined and after ABS control has terminated.

z

A malfunction DTC will set.

z

The ABS indicator turns on.

z

The TCS indicator turns on.

z

The Red BRAKE Warning indicator turns on.

Conditions for Clearing the DTC

z

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

z

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

z

It is very important that a thorough inspection of the wiring and connectors be performed. Failure to
carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement
with reappearance of the malfunction.

z

Thoroughly inspect any circuitry that may be causing the 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

z

The following conditions may cause an intermittent malfunction:

{

A poor connection

{

Rubbed-through wire insulation

{

A broken wire inside the insulation

z

If the customer's comments reflect that the amber ABS/TCS indicator is on only during moist
environmental conditions (rain, snow, vehicle wash), inspect all the wheel speed sensor circuitry for signs

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2