Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Aids
Thoroughly inspect the wiring and connectors when diagnosing intermittent DTCs. This will include the following:
- Removal of the protective conduit and inspection of wiring for damage, shorts, and contamination
- Inspection for improperly formed and/or damaged terminals
- Checking terminal contact retention force by using a spare male/female terminal
- Removal of the terminals from the connectors to check for proper terminal to wire crimp
If the driver comments reflect that the ABS warning lamp is ON only during moist environmental changes, such as rain, snow, vehicle wash, the all wheel speed sensor circuitry should be thoroughly inspected for signs of water intrusion. If the DTC is not current, simulate the effects of water intrusion. Use the following procedure. Spray the suspected area with a 5 percent salt-water solution. Then test drive the vehicle over various road surfaces such as, bumps, turns, etc., above 24 km/h (15 mph). If the DTC sets then replace the suspected harness and/or sensor.
When measuring wheel speed sensor resistance, ensure the vehicle is at room temperature, since resistance will increase with temperature.
Failure to perform the previous steps carefully and fully can result in misdiagnosis, unnecessary component replacement, and reoccurrence of DTC C1205.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Antilock Brake System Schematics (Notchback) or Antilock Brake System Schematics (Hatchback) Connector End View Reference: Antilock Brake System Connector End Views (Notchback) or Antilock Brake System Connector End Views (Hatchback) |
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| 1 | Did you perform the Diagnostic System Check - Vehicle? | - | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 |
|
- | Go to Step 3 | Go to Step 4 |
| 3 | Repair the damage to the right front wheel speed sensor, and/or jumper harness. Did you find and correct the condition? |
- | Go to Step 18 | - |
| 4 | Was DTC C1203 set as a current or history code? | - | Go to DTC C1203 | Go to Step 5 |
| 5 |
|
- | Go to Step 6 | Go to Diagnostic Aids |
| 6 |
|
100 mV | Go to Step 7 | Go to Step 8 |
| 7 | Replace the EBCM. Refer to Brake Modulator Assembly Replacement . Did you complete the replacement? |
- | Go to Step 18 | - |
| 8 |
|
800-1600 Ω | Go to Step 10 | Go to Step 9 |
| 9 | Replace the right front wheel speed sensor. Refer to Front Wheel Speed Sensor Replacement . Did you complete the replacement? |
- | Go to Step 18 | - |
| 10 |
|
100 mV | Go to Step 11 | Go to Step 9 |
| 11 |
|
OL (open circuit) | Go to Step 13 | Go to Step 12 |
| 12 | Find and repair the short between the two circuits. Did you find and correct the condition? |
- | System OK | - |
| 13 |
|
2 Ω | Go to Step 15 | Go to Step 14 |
| 14 | Repair the open or high resistance between terminals 1 and 2. Did you find and correct the condition? |
- | Go to Step 18 | - |
| 15 |
|
2 Ω | Go to Step 17 | Go to Step 16 |
| 16 | Repair the open or high resistance between terminal 2 and 1. Did you find and correct the condition? |
- | Go to Step 18 | - |
| 17 |
|
- | Go to Step 7 | Go to Step 18 |
| 18 |
|
- | Go to Step 2 | System OK |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.