For 1990-2009 cars

Table 1: | DTC C0056 Rear Wheel Speed Circuit Range/Performance

ABS Components
Antilock Brake System Schematics

### Circuit Description

The speed sensor used on this vehicle is a single point magnetic pickup. This sensor produces an AC signal that the EBCM uses the frequency from to calculate the wheel speed.

### Conditions for Setting the DTC

• | The DTC will set if one wheel speed = 0 and the other WSS are greater than 40 Km/h (25 mph) for 10 ms, or if the EBCM detects a short to ground.

• | The DTC will set if during drive off, one wheel speed = 0, and the other WSS are greater than 12 Km/h (7.5 mph).

### Action Taken When the DTC Sets

• | A malfunction DTC stores.

• | The ABS disables.

• | The amber ABS indicator turns on.

• | The Red BRAKE Warning indicator turns on.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

• | 100 ignition cycles pass with no DTC(s) detected.

| Important: After the DTC is cleared by ignition cycle default, the vehicle must be driven above 12 Km/h (8 mph) for the ABS/TCS indicator(s) to turn off.

### Diagnostic Aids

• | 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.

• | 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

• | The following conditions may cause an intermittent malfunction:

- | A poor connection

- | Rubbed-through wire insulation

- | A broken wire inside the insulation

• | If the customer's comments reflect that the amber ABS indicator is on only during moist environmental conditions (rain, snow, vehicle wash), inspect all the wheel speed sensor circuitry 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 five percent saltwater solution.

Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.

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 harness.

• | If an intermittent malfunction exists refer to Troubleshooting Procedures Cell 4 in Electrical Diagnosis for further diagnosis.

### Rear Wheel Speed Sensor Resistance

The following table contains resistance values for the rear wheel speed sensors at varying sensor temperatures for use in diagnosis. The values are approximate and should be used as a guideline for diagnosis.

Sensor Temperature (°C) | Sensor Temperature (°F) | Sensor Resistance (Ohms)
--- | --- | ---
-34 to 4 | -30 to 40 | 763 to 1110
5 to 43 | 41 to 110 | 908 to 1292
44 to 93 | 111 to 200 | 1057 to 1525

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. This step checks for the proper resistance in the WSS.

2. This step checks for the proper WSS output.

#### DTC C0056 Rear Wheel Speed Circuit Range/Performance

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 | Inspect the WSS for physical damage. Is physical damage of the WSS evident? | -- | Go to Step 3 | Go to Step 4
3 | Replace the WSS. Refer to Wheel Speed Sensor Replacement . Is the replacement complete? | -- | Go to Step 16 | --
4 | Inspect the jumper harness for physical damage. Is physical damage of the jumper harness evident? | -- | Go to Step 5 | Go to Step 6
5 | Replace the jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the replacement complete? | -- | Go to Step 16 | --
6 |

1. Disconnect the WSS connector directly at the WSS.
2. Using J 39200 DMM, measure the resistance between terminals A and B of the WSS.

Is the resistance within the range specified in the value(s) column?

763-1525 ohms

Go to Step 7

Go to Step 3

7 |

1. With the J 39200 DMM still connected to the WSS select the mV AC scale.
2. Spin the rear wheel as fast as you can by hand while monitoring the AC output.

Is the AC voltage within the range specified in the value(s) column?

Above 100 mV

Go to Step 8

Go to Step 3

8 | Using J 39200 DMM, measure the resistance between the WSS terminal A and ground. Is the resistance within the range specified in the value(s) column? | OL (infinite) | Go to Step 9 | Go to Step 3
9 |

1. Disconnect the EBCM/EBTCM harness connector C1.
2. Install the J 39700 Universal Pinout Box using the J 39700-530 cable adapter to the EBCM/EBTCM harness connector C1 only.
3. Using J 39200 DMM, measure the resistance between terminals 22 and 23 of J 39700 .

Is the resistance within the range specified in the values column?

OL (infinite)

Go to Step 11

Go to Step 10

10 | Repair short between CKT(s) 884 and 885. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. If a short between wheel speed circuits is found in the jumper harness, replace the jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Step 16

--

11 | Using J 39200 DMM, measure the resistance between terminals 22 and 15 of J 39700 . Is the resistance within the range specified in the values column? | OL (infinite) | Go to Step 13 | Go to Step 12
12 | Repair CKT 884 for a short to ground. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. If a short to ground is found in the jumper harness, replace the jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | Go to Step 16 | --
13 | Using J 39200 DMM, measure the resistance between terminals 23 and 15 of J 39700 . Is the resistance within the range specified in the values column? | OL (infinite) | Go to Step 15 | Go to Step 14
14 | Repair CKT 885 for a short to ground. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. If a short to ground is found in the jumper harness, replace the jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | Go to Step 16 | --
15 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check - ABS | --
16 |

1. Reconnect all previously disconnected components.
2. Using a scan tool clear the DTC.
3. Remove the scan tool from the DLC.
4. Carefully drive vehicle above 12 Km/h (8 mph) for several minutes.

Does the DTC reset as a current DTC?

--

Go to Step 2

Go to Diagnostic System Check - ABS