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 C1227 can set when the brake is OFF. |
| • | DTC C1227 detects a situation in which the left rear wheel acceleration or deceleration is beyond specified limits. |
| • | This DTC will not set if DTC C1234 has already set. |
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 an intermittent malfunction:
| • | A poor connection |
| • | Rubbed-through wire insulation |
| • | A broken wire inside the insulation |
| • | Loose wheel speed sensor |
| • | Worn suspension components |
| • | Wheel speed sensor physically damaged |
| • | Wheel speed sensor ring damaged |
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:
- Inspect the wheel speed sensor terminals and harness connector for corrosion and/or water intrusion.
- Replace the wheel speed sensor jumper harness if evidence of corrosion or water intrusion exists.
Test Description
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This test checks the wheel speed sensor for the proper resistance value.
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This test ensures that the wheel speed sensor generates the proper voltage.
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This test checks for a short between the wheel speed sensor high and low circuits.
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This test determines if a wheel speed sensor circuit could be shorted when the EBCM is connected.
Step | Action | Value(s) | Yes | No | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual. Important: Difficulty may occur when trying to locate the 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 the 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? | -- | ||||||||||||||||
2 |
Is there any physical damage? | -- | ||||||||||||||||
3 | Inspect the following components for physical damage:
Is there any physical damage? | -- | ||||||||||||||||
Is the resistance within the specified range? | 1050-1450 ohms | |||||||||||||||||
Is the voltage equal to or greater than the specified voltage? | 100 mV | |||||||||||||||||
Is the resistance within the specified range? | OL (Infinite) | |||||||||||||||||
7 |
Are there signs of poor terminal contact, corrosion, or damaged terminals? | -- | ||||||||||||||||
8 | Inspect the wiring between the left rear WSS and the EBCM for signs of damage that may cause a short between the circuits. Are there any signs of damaged wiring? | -- | ||||||||||||||||
9 | Inspect the harness connectors between the left rear WSS and the EBCM for signs of damage that may cause a short between the circuits. Are there any signs of damaged connectors? | -- | ||||||||||||||||
Does DTC C1227 set as a current DTC? | -- | |||||||||||||||||
11 |
Is the speed of the left rear wheel speed sensor constantly higher or lower than the speed of the three remaining wheel speed sensors? | -- | ||||||||||||||||
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? | -- | -- | |||||||||||||||
13 | Replace the damaged wiring harness that caused the short in the circuits between the left rear WSS and the EBCM. Is the repair complete? | -- | -- | |||||||||||||||
14 | Replace the damaged wiring harness connectors that caused the short in the circuits between the left rear WSS and the EBCM. Is the repair complete? | -- | -- | |||||||||||||||
15 | Replace the left rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | -- | |||||||||||||||
16 | Replace the left rear wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | -- | |||||||||||||||
17 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | -- | |||||||||||||||
18 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the repair complete? | -- | System OK | -- | ||||||||||||||
