For 1990-2009 cars
ABS Components
Cell 44: Stoplamp/BTSI Switch, Inlet/Outlet Solenoid Valves, and Wheel Speed Sensors
Handling ESD Sensitive Parts Notice

### Circuit Description

The wheel speed sensor creates an AC voltage as each wheel turns. The frequency of the voltage is proportional to the wheel speed.

The voltage is magnetically induced. The voltage is caused by a toothed sensor ring (mounted on the drive axle) which passes the stationary pickup coil of the wheel speed sensor.

The EBCM/EBTCM uses the wheel speed sensor signal in order to calculate the following values:

• | The vehicle reference speeds

• | The speed of each wheel

• | The acceleration

• | The slip values

Use these values in order to determine when antilock or traction control (when equipped) is required.

### Conditions for Setting the DTC

The DTC C1227 sets under the following conditions:

• | The EBCM/EBTCM does not see any wheel speed sensor signal.

• | The EBCM/EBTCM determines that continuity exists in the circuit.

One of the following conditions may cause the DTC C1227 to set:

• | A dislodged wheel speed sensor

• | A missing toothed sensor ring (front)

• | A defective hub and bearing assembly (rear)

### Action Taken When the DTC Sets

The following actions will be taken when the DTC sets:

• | A malfunction DTC is stored.

• | The ABS is disabled.

• | The ANTILOCK indicator lamp is turned ON.

### Conditions for Clearing the DTC

The DTC will be cleared under following conditions:

• | Conditions for the malfunction are no longer present. Use the scan tool clear DTCs function.

• | 100 ignition switch key cycles have passed with no malfunctions detected.

### Diagnostic Aids

One of the following conditions may cause an intermittent malfunction:

• | A poor connection

• | A rubbed through wire insulation

• | A wire that is broken inside the insulation

Inspect any suspect circuitry 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

### Test Description

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

1. This step ensures that the sensor is capable of putting out the necessary voltage to the EBCM/EBTCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check
2 |

1. Inspect the left front wheel speed sensor wiring connectors for damage.
2. Inspect the left front wheel speed sensor for looseness or damage.

Does the sensor have any physical damage?

--

Go to Step 7

Go to Step 3

3 |

1. Disconnect the left front wheel speed sensor directly at the sensor.
2. Use the J 39200 digital multimeter (DMM) in order to measure the resistance between terminal A and terminal B of the left front wheel speed sensor.

Is the resistance within the specified range?

850-1350 ohms

Go to Step 4

Go to Step 8

4 | Spin the wheel by hand as quickly as possible while monitoring the AC output. Is the AC voltage greater than the specified value? | 100 mV | Go to Step 5 | Go to Step 8
5 |

1. Disconnect the EBCM/EBTCM harness connector.
2. Use the J 39200 DMM in order to measure the resistance between terminal 30 and terminal 48.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 6

Go to Step 9

6 |

1. Reconnect all of the connectors.
2. Test drive the vehicle above 24 km/h (15 mph) for at least 30 seconds while monitoring the scan tool for ABS/TCS DTCs.

Does the DTC C1227 reset?

--

Go to Step 10

Go to Diagnostic System Check

7 |

1. Repair or replace the damaged components as necessary. Refer to Wiring Repairs in Wiring Systems or Front Wheel Bearing and Hub Replacement in Front Suspension.
2. Drive the vehicle above 24 km/h (15 mph) while monitoring a scan tool in order to ensure that the DTC does not reset.

Does the DTC C1227 reset?

--

Go to Step 3

Go to Diagnostic System Check

8 | Replace the left front wheel speed sensor. Refer to Front Wheel Bearing and Hub Replacement in Front Suspension. Is the repair complete? | -- | Go to Step 11 | --
9 | Repair the short between CKT 873 and CKT 830. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 11 | --
10 | Replace the EBCM/EBTCM. Refer to Electronic Brake and Traction Control Module Replacement . Is the repair complete? | -- | Go to Step 11 | --
11 | Test drive the vehicle above 24 km/h (15 mph) for at least 30 seconds while monitoring the scan tool for ABS/TCS DTCs. Does the DTC C1227 reset? | -- | Go to Step 2 | Go to Diagnostic System Check