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 C1222 sets when the vehicle is not in an ABS stop.
A malfunction exists if both of the following conditions occur:
| • | The right front wheel speed sensor input signal equals zero. |
| • | The vehicle's reference speed is greater than 8 km/h (5 mph) |
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 DTC(s) detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition switch to the OFF position. |
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 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 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:
- Spray the suspected area with a 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, replace the suspected harness.
Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.
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 and jumper harness if evidence of corrosion or water intrusion exists.
Refer to On-Vehicle Service.
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 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 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? | 1530-1870 ohms | ||||||||||||||||
5 |
Is the voltage equal to or greater than the specified voltage? | 100 mV | ||||||||||||||||
6 |
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 of CKT 872 and CKT 833 for signs of damage that may cause a short between CKT 872 and CKT 833. Are there any signs of damaged wiring? | -- | ||||||||||||||||
9 | Inspect the harness connectors of CKT 872 and CKT 833 for signs of damage that may cause a short between CKT 872 and CKT 833. Are there any signs of damaged connectors? | -- | ||||||||||||||||
10 |
Does DTC C1222 set as a current DTC? | -- | ||||||||||||||||
11 |
Is the speed of the right front wheel speed sensor constantly higher 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). Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
13 | Replace the damaged wiring harness that causes the short between CKT 872 and CKT 833. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
14 | Replace the damaged wiring harness connectors that cause the short between CKT 872 and CKT 833. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
15 | Replace the right front wheel speed sensor jumper harness. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
16 | Replace the right front wheel speed sensor. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
17 | Replace the EBCM. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||||||||||
18 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. | -- | -- | -- | ||||||||||||||
