Circuit Description
The rotational movement of the toothed ring past the wheel speed sensor causes a change in the electromagnetic field which produces an AC voltage signal by the wheel speed sensor. The frequency of the sinusoidal (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.
Action Taken When the DTC Sets
| • | A malfunction DTC stores. |
| • | The ABS/TCS disables. |
| • | The amber ABS/TCS warning indicators turn on. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTC function is used. |
| • | 100 drive cycles pass with no DTC detected. |
Diagnostic Aids
The following conditions may cause an intermittent malfunction:
| • | A poor connection |
| • | Rubbed-through wire insulation |
| • | A broken wire inside the insulation |
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual or Scan Tool Diagnostics located in this section for the procedure.
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 of 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:
- Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.
- Spray the suspected area with the five percent saltwater solution.
- Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 24 km/h (15 mph) for at least 30 seconds.
- If the DTC returns, inspect the suspected circuits.
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 |
| • | Corrosion and/or water intrusion of terminals. |
Important: Difficulty may occur when trying to locate the intermittent malfunctions in the wheel speed sensor. 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.
Rear Wheel Speed Sensor Resistance
Resistance of the wheel speed sensor will increase with an increase in sensor temperature.
The following table contains resistance values for the rear wheel speed sensors at varying temperatures for use in diagnosis. The values are approximate and should be used as a guideline for diagnosis.
Important: Zero the J 39200 test leads before making any resistance measurements.
Temperature (°C) | Temperature (°F) | Resistance (Ohms) |
|---|---|---|
-34 to 4 | -30 to 40 | 800 to 1100 |
5 to 43 | 41 to 110 | 950 to 1300 |
44 to 93 | 111 to 200 | 1100 to 1600 |
Step | Action | Value(s) | Yes | No | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |||||||||||||||
2 |
Is there any physical damage? | -- | ||||||||||||||||
3 | Inspect the following components for physical damage:
Is there any physical damage? | -- | ||||||||||||||||
4 |
Is the resistance within the specified range? | 1030-1180 ohms at 20°C (68°F) | ||||||||||||||||
5 |
Is the voltage equal to or greater than the specified voltage? | 100 mV | ||||||||||||||||
6 |
Is continuity present between the 24-way EBCM/EBTCM connector C1 terminal A3 and terminal B2? | -- | ||||||||||||||||
7 |
Are there signs of poor terminal contact, corrosion, or damaged terminals? | -- | ||||||||||||||||
8 | Repair the short between CKT 885 and CKT 884. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
9 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal B2 and ground. Is continuity present between the 24-way EBCM/EBTCM connector C1 terminal B2 and ground? | -- | ||||||||||||||||
10 | Repair the short to ground in CKT 885. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
11 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal A3 and ground. Is continuity present between the 24-way EBCM/EBTCM connector C1 terminal A3 and ground? | -- | ||||||||||||||||
12 | Repair the short to ground in CKT 884. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
13 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal B2 and the wheel speed sensor connector terminal B. Is continuity present in CKT 885 between the 24-way EBCM/EBTCM connector C1 terminal B2 and the wheel speed sensor connector terminal B? | -- | ||||||||||||||||
14 | Repair the open or high resistance in CKT 885. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
15 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal A3 and the wheel speed sensor connector terminal A. Is continuity present in CKT 884 between the 24-way EBCM/EBTCM connector C1 terminal A3 and the wheel speed sensor connector terminal A? | -- | ||||||||||||||||
16 | Repair the open or high resistance in CKT 884. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
17 |
Does DTC C1223 set as a current DTC? | -- | ||||||||||||||||
18 |
Is the speed of the left rear wheel speed sensor constantly higher than the speed of the three remaining wheel speed sensors? | -- | ||||||||||||||||
19 | Replace the EBCM/EBTCM. Refer to Electronic Brake and Traction Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
20 | Is the malfunction intermittent or not present at this time? | -- | Go to Diagnostic Aids | Go to Diagnostic System Check | ||||||||||||||
21 | Replace all of the terminals that exhibit signs of poor terminal contact, corrosion, or damaged terminals. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
22 | Replace the left rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
23 | Replace the left rear wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
