For 1990-2009 cars
ABS Components
Cell 44: Wheel Speed Sensors and Motor Pack
Handling ESD Sensitive Parts Notice

### Circuit Description

As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce an AC voltage signal. The frequency of the AC voltage signal is proportional to the wheel speed. The amplitude of the AC voltage signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring. The proximity of the wheel speed sensor to the toothed ring is also referred to as the air gap.

### Conditions for Setting the DTC

DTC C1224 can set when the vehicle is not in an ABS stop.

A malfunction exists if both of the following conditions occur:

• | The right rear wheel speed sensor input signal equals zero

• | The vehicle's reference speed is greater than 8 km/h (5 mph)

• | This DTC will not set if DTC C1235 has already failed

### Action Taken When the DTC Sets

• | A malfunction DTC stores.

• | The ABS disables.

• | The ABS 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 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

### Diagnostic Aids

The following conditions may cause a malfunction:

• | A poor connection

• | Rubbed-through wire insulation

• | A broken wire inside the insulation

• | Wheel speed sensor physically damaged

• | Wheel speed sensor input circuits shorted together

• | Missing speed sensor ring

• | Excessive wheel speed sensor gap

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.

If the customer's comments reflect that the amber ABS warning indicator is ON only during moist environmental changes (rain, snow, vehicle wash), inspect all the wheel speed sensor circuitry for signs of water intrusion.

Thoroughly inspect any circuitry that may be causing the intermittent 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

Resistance of the wheel speed sensor will increase with an increase in sensor temperature.

Use the following procedure when replacing a wheel speed sensor or harness:

1. Inspect the wheel speed sensor terminals and harness connector for corrosion and/or water intrusion.
2. Replace the wheel speed sensor and jumper harness if evidence of corrosion or water intrusion exists.

Two separate wheel speed = 0 DTCs will be set if two wheel speeds are 0 km/h (0 mph) for greater than 20 seconds while the remaining wheel speed(s) are greater than 16 km/h (10 mph) and within 11 km/h (6.8 mph).

### Test Description

1. This test checks the wheel speed sensor for the proper resistance value.

2. This test ensures that the wheel speed sensor generates the proper voltage.

3. This test checks for a short between the wheel speed sensor high and low circuits.

4. This test determines if a wheel speed sensor circuit could be shorted when the EBCM is connected.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual. Important: Difficulty may occur in trying to locate intermittent malfunctions in the wheel speed sensor circuit. Do not disturb any of the electrical connections. Change electrical connections only when instructed to do so by a step in the diagnostic table. Changing electrical connections at the correct time will ensure that an intermittent electrical connection will not be corrected until the source of the malfunction is found.
1 | Was A Diagnostic System Check-ABS performed? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 |

1. Turn the ignition switch to the OFF position.
2. Inspect the right rear wheel speed sensor and the right rear wheel speed sensor harness connector for physical damage.

Is there any physical damage?

--

Go to Step 16

Go to Step 3

3 | Inspect the following components for physical damage:

• | The right rear wheel speed sensor jumper harness

• | The right rear wheel speed sensor jumper harness connectors

Is there any physical damage?

--

Go to Step 15

Go to Step 4

4 |

1. Disconnect the right rear wheel speed sensor directly at the right rear wheel speed sensor connector.
2. Use the J 39200 in order to measure the resistance between the right rear wheel speed sensor connector terminal A and the right rear wheel speed sensor connector terminal B.

Is the resistance within the specified range?

1050-1450 ohms

Go to Step 5

Go to Step 16

5 |

1. Select the A/C VOLTAGE scale on the J 39200 .
2. Spin the right rear wheel by hand while observing the voltage reading on the J 39200 .

Is the voltage equal to or greater than the specified voltage?

100 mV

Go to Step 6

Go to Step 16

6 |

1. Disconnect the EBCM connector.
2. Use the J 39200 in order to measure the resistance between the EBCM connector terminal A2 and the EBCM connector terminal B1.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 7

Go to Step 8

7 |

1. Inspect the EBCM connector for the following conditions:

• | Damage

• | Poor terminal contact

• | Terminal corrosion

• | Damage, poor terminal contact, and terminal corrosion may cause a short between the EBCM connector terminal A2 and the EBCM connector terminal B1.

2. Inspect the remaining terminals of the EBCM connector for the following conditions:

• | Damage

• | Poor terminal contact

• | Terminal corrosion

Are there signs of poor terminal contact, corrosion, or damaged terminals?

--

Go to Step 12

Go to Step 8

8 | Inspect the wiring between the right rear WSS and the EBCM for signs of damage that may cause a short between the circuits. Are there any signs of damaged wiring? | -- | Go to Step 13 | Go to Step 9
9 | Inspect the harness connectors between the right rear WSS and the EBCM for signs of damage that may cause a short between the circuits. Are there any signs of damaged connectors? | -- | Go to Step 14 | Go to Step 10
10 |

1. Reconnect the EBCM harness connector.
2. Reconnect the right rear wheel speed sensor harness connector.
3. Install a Scan Tool .
4. Test drive the vehicle at a speed above 24 km/h (15 mph) for at least 30 seconds.
5. Use the Scan Tool in order to read the DTCs.

Does DTC C1224 set as a current DTC?

--

Go to Step 11

Go to Step 18

11 |

1. Select Data Display on the Scan Tool .
2. Select ABS Data.
3. Monitor the wheel speed sensor speeds.
4. Drive the vehicle in the following manner:

4.1. | Slowly accelerate to 65 km/h (40 mph).

4.2. | Slowly decelerate to 0 km/h (0 mph).

Is the speed of the right rear wheel speed sensor constantly lower than the speed of the three remaining wheel speed sensors?

--

Go to Step 16

Go to Step 17

12 | Replace all of the terminals that exhibit signs of poor terminal contact, corrosion, or damaged terminal(s). Refer to Connector Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
13 | Replace the damaged wiring harness that caused the short in the circuits between the right rear WSS and the EBCM. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
14 | Replace the damaged wiring harness connectors that caused the short in the circuits between the left front WSS and the EBCM. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
15 | Replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
16 | Replace the right rear wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
17 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
18 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the action complete? | -- | System OK | --