Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) CHECK FOR A DTC C1020-LEFT REAR WHEEL SPEED SENSOR CIRCUIT
NOTE: This DTC must be active for the results of this test to be valid.

Turn the ignition on.

With the scan tool, read DTCs.

Record DTC and Freeze Frame information.

With the scan tool, erase DTCs.

Cycle the ignition switch off then on.

With the scan tool, read DTCs.

Does the scan tool display: C1020-LEFT REAR WHEEL SPEED SENSOR CIRCUIT?

Yes
1. Go To step 2).
No
1. Refer ABS-INTERMITTENT CONDITION .
2. Perform ABS VERIFICATION TEST - VER 1 .
2) CHECK THE TERMINALS/CONNECTORS/TONE WHEEL FOR DAMAGE
NOTE: Check all related wiring for bruised, chafed, pierced, or partially broken wires.

NOTE: Check all related connectors for broken, bent, pushed out, or corroded terminals.

NOTE: Check the tone wheel teeth for missing teeth, cracks, or looseness. Teeth should be perfectly square, not bent, or nicked.

Turn the ignition off.

Inspect the Anti-Lock Brake Module harness connector, Left Rear WSS, Left Rear WSS harness connector, and Left Rear WSS tone wheel (if applicable).

Were any problems found?

Yes
1. Repair as necessary.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Go To step 3).
3) (B3) LEFT REAR WSS SIGNAL CIRCUIT SHORTED TO THE (B4) LEFT REAR WSS SUPPLY CIRCUIT

Fig 1: Checking Left Rear WSS Signal Circuit & Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left Rear WSS harness connector.

Measure the resistance between the (B3) Left Rear WSS Signal and the (B4) Left Rear WSS Supply circuits at the Left Rear WSS harness connector.

Is the resistance above 5.0 ohms?

Yes
1. Go To step 4).
No
1. Repair the (B3) Left Rear WSS Signal circuit for a short to the (B4) Left Rear WSS Supply circuit.
2. Perform ABS VERIFICATION TEST - VER 1 .
4) CHECK THE VOLTAGE ON THE (B4) LEFT REAR WSS SUPPLY CIRCUIT

Fig 2: Checking Left Rear WSS Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Connect the Anti-Lock Brake Module harness connector.

Turn the ignition on.

Measure the voltage of the (B4) Left Rear WSS Supply circuit in the Left Rear WSS harness connector.

Is the voltage above 10 volts?

Yes
1. Go To step 8).
No
1. Go To step 5).
5) (B4) LEFT REAR WSS SUPPLY CIRCUIT SHORT TO VOLTAGE

Fig 3: Checking Left Rear WSS Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Turn the ignition on.

Measure the voltage of the (B4) Left Rear WSS Supply circuit.

Is there any voltage present?

Yes
1. Repair the (B4) Left Rear WSS Supply circuit for a short to voltage.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Go To step 6).
6) (B4) LEFT REAR WSS SUPPLY CIRCUIT SHORT TO GROUND

Fig 4: Checking Left Rear WSS Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Measure the resistance between ground and the (B4) Left Rear WSS Supply circuit.

Is the resistance below 5.0 ohms?

Yes
1. Repair the (B4) Left Rear WSS Supply circuit for a short to ground.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Go To step 7).
7) (B4) LEFT REAR WSS SUPPLY CIRCUIT OPEN

Fig 5: Checking Left Rear WSS Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (B4) Left Rear WSS Supply circuit.

Is the resistance below 5.0 ohms?

Yes
1. Replace the Anti-Lock Brake Module in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Repair the (B4) Left Rear WSS Supply circuit for an open.
2. Perform ABS VERIFICATION TEST - VER 1 .
8) CHECK THE (B4) LEFT REAR WSS SUPPLY AND THE (B3) LEFT REAR WSS SIGNAL VOLTAGE

Fig 6: Checking Left Rear WSS Signal Circuit & Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the voltage between the (B4) Left Rear WSS Supply and (B3) Left Rear WSS Signal circuits at the Left Rear WSS harness connector.

Is the voltage above 10 volts?

Yes
1. Go To step 11).
No
1. Go To step 9).
9) (B3) LEFT REAR WSS SIGNAL CIRCUIT SHORT TO VOLTAGE

Fig 7: Checking Left Rear WSS Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Turn the ignition on.

Measure the voltage of the (B3) Left Rear WSS Signal circuit.

Is there any voltage present?

Yes
1. Repair the (B3) Left Rear WSS Signal circuit for a short to voltage.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Go To step 10).
10) (B3) LEFT REAR WSS SIGNAL CIRCUIT OPEN

Fig 8: Checking Left Rear WSS Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Measure the resistance of the (B3) Left Rear WSS Signal circuit.

Is the resistance above 5.0 ohms?

Yes
1. Repair the (B3) Left Rear WSS Signal circuit for an open.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Replace the Anti-Lock Brake Module in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST - VER 1 .
11) CHECK THE (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR A SHORT TO GROUND

Fig 9: Checking Left Rear WSS Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Measure the resistance between ground and the (B3) Left Rear WSS Signal circuit.

Is the resistance below 5.0 ohms?

Yes
1. Repair the (B3) Left Rear WSS Signal circuit for a short to ground.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Go To step 12).
12) CHECK THE (B3) LEFT REAR WSS SIGNAL VOLTAGE AT THE LEFT REAR WSS HARNESS CONNECTOR

Fig 10: Checking Left Rear WSS Signal Voltage
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Reconnect all connectors.

Turn the ignition on.

While back probing, measure the voltage between the (B3) Left Rear WSS Signal circuit at the Left Rear WSS harness connector and ground.

Slowly rotate the wheel by hand.

Does the (B3) Left Rear WSS Signal circuit voltage toggle between approximately 1.6 and.8 volts?

Yes
1. Go To step 13).
No
1. Replace the Left Rear WSS in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST - VER 1 .
13) CHECK THE (B3) LEFT REAR WSS SIGNAL VOLTAGE AT THE ANTI-LOCK BRAKE MODULE HARNESS CONNECTOR

Fig 11: Checking Left Rear WSS Signal Voltage
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Turn the ignition on.

While back probing, measure the voltage between the (B3) Left Rear WSS Signal circuit at the Anti-Lock Brake Module harness connector and ground.

Slowly rotate the wheel by hand.

Does the (B3) Left Rear WSS Signal circuit voltage toggle between approximately 1.6 and.8 volts?

Yes
1. Replace the Anti-Lock Brake Module in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST - VER 1 .
No
1. Repair the (B3) Left Rear WSS Signal circuit for an open.
2. Perform ABS VERIFICATION TEST - VER 1 .