For 1990-2009 cars
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice

### 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 C1233 can set anytime after initialization.

A malfunction exists if either of the right front wheel speed sensor circuits are open or shorted to voltage or ground.

### 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:

1. Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.
2. Spray the suspected area with the five percent saltwater solution.
3. Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 24 km/h (15 mph) for at least 30 seconds.
4. 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.

### Front 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 front 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 | 804 to 1066
5 to 43 | 41 to 110 | 956 to 1240
44 to 93 | 111 to 200 | 112 to 1463

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

1. Turn the ignition switch to the OFF position.
2. Make a 5 percent saltwater solution.
3. Thoroughly spray the right front wheel speed sensor jumper harness with the saltwater solution.
4. Disconnect the 24-way EBCM/EBTCM harness connector C1.
5. Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM harness connector C1 terminal A4 and the 24-way EBCM/EBTCM harness connector C1 terminal B3.

Is the resistance within the specified range?

1020-1137 ohms at 20°C (68°F)

Go to Step 3

Go to Step 11

3 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM harness connector C1 terminal B3 and ground. Is continuity to ground present? | -- | Go to Step 14 | Go to Step 4
4 |

1. Turn the ignition switch to the RUN position (Do not start the engine).
2. Use the J 39200 in order to measure the voltage between the 24-way EBCM/EBTCM harness connector C1 terminal B3 and ground.

Is the voltage equal to the specified value?

0.00 V

Go to Step 7

Go to Step 5

5 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the right front wheel speed sensor at the right front wheel speed sensor connector.
3. Turn the ignition switch to the RUN position, engine off.
4. Use the J 39200 in order to measure the voltage between the 24-way EBCM/EBTCM harness connector C1 terminal B3 and ground.

Is the voltage equal to the specified value?

0.00 V

Go to Step 6

Go to Step 19

6 | Use the J 39200 in order to measure the voltage between the 24-way EBCM/EBTCM harness connector C1 terminal A4 and ground. Is the voltage equal to the specified value? | 0.00 V | Go to Step 31 | Go to Step 20
7 |

1. Turn the ignition switch to the OFF position.
2. Inspect the following terminals:

• | The 24-way EBCM/EBTCM connector C1 terminal A4 and terminal B3

• | The remaining terminals of the 24-way EBCM/EBTCM connector C1

3. Inspect the above terminals for the following conditions:

• | Terminal damage

• | Poor terminal contact

• | Terminal corrosion

• | Terminal damage, terminal corrosion, and poor terminal contact may cause an open circuit, a short to voltage, or a short to ground.

Are there signs of poor terminal contact, terminal corrosion, or damaged terminals?

--

Go to Step 27

Go to Step 8

8 | Inspect the wiring of CKT 833 and CKT 872 for signs of wire damage. Wire damage may cause the following conditions in CKT 833 and CKT 872:

• | An open circuit

• | A short to voltage

• | A short to ground

Are there signs of damaged wiring?

--

Go to Step 21

Go to Step 9

9 | Inspect the harness connectors of CKT 833 and CKT 872 for signs of wire damage. Wire damage may cause the following conditions in CKT 833 and CKT 872:

• | An open circuit

• | A short to voltage

• | A short to ground

Are there signs of damaged connectors?

--

Go to Step 22

Go to Step 10

10 |

1. Reconnect the 24-way EBCM/EBTCM connector C1.
2. Reconnect the right front wheel speed sensor harness connector.
3. Install a scan tool.
4. Test drive the vehicle at a speed above 24 km/h (15 mph) for at least 30 seconds.
5. Use the scan tool in order to read the DTCs.

Does DTC C1233 set as a current DTC?

--

Go to Step 30

Go to Step 31

11 |

1. Disconnect the right front wheel speed sensor directly at the right front wheel speed sensor connector.
2. Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal B3 and the right front wheel speed sensor harness connector terminal B.

Is the resistance within the specified range?

0-2 ohms

Go to Step 12

Go to Step 23

12 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal A4 and the right front wheel speed sensor harness connector terminal A. Is the resistance within the specified range? | 0-2 ohms | Go to Step 13 | Go to Step 24
13 | Use the J 39200 in order to measure the resistance between the right front wheel speed sensor connector terminal A and the right front wheel speed sensor connector terminal B. Is the resistance within the specified range? | 1020-1137 ohms at 20°C (68°F) | Go to Step 31 | Go to Step 28
14 |

1. Disconnect the connector C172.
2. Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal B3 and ground.

Is continuity to ground present?

--

Go to Step 25

Go to Step 15

15 | Use the J 39200 in order to measure the resistance between the 24-way EBCM/EBTCM connector C1 terminal A4 and ground. Is continuity to ground present? | -- | Go to Step 26 | Go to Step 16
16 |

1. Thoroughly respray the right front wheel speed sensor jumper harness with the saltwater solution.
2. Disconnect the right front wheel speed sensor directly at the right front wheel speed sensor.
3. Use the J 39200 in order to measure the resistance between the right front wheel speed sensor jumper harness connector terminal A (leading towards the EBCM/EBTCM ) and ground.

Is continuity to ground present?

--

Go to Step 29

Go to Step 17

17 | Use the J 39200 in order to measure the resistance between the right front wheel speed sensor jumper harness connector terminal B (leading towards the EBCM/EBTCM ) and ground. Is continuity to ground present? | -- | Go to Step 29 | Go to Step 18
18 | Use the J 39200 in order to measure the resistance between the right front wheel speed sensor jumper connector terminal A (leading towards the wheel speed sensor) and ground. Is continuity to ground present? | -- | Go to Step 28 | Go to Step 31
19 |

1. Repair the short to voltage in CKT 833.
2. If the short to voltage is found in the right front wheel speed sensor jumper harness replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

20 |

1. Repair the short to voltage in CKT 872.
2. If the short to voltage is found in the right front wheel speed sensor jumper harness replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

21 |

1. Repair the wiring damage in CKT 833 or CKT 872.
2. If the wiring damage is found in the right front wheel speed sensor jumper harness replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

22 |

1. Repair the connector damage in CKT 833 or CKT 872.
2. If the connector damage is found in the right front wheel speed sensor jumper harness, replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

23 |

1. Repair the open or high resistance in CKT 833.
2. If the open or high resistance is found in the right front wheel speed sensor jumper harness, replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

24 |

1. Repair the open or high resistance in CKT 872.
2. If the open or high resistance is found in the right front wheel speed sensor jumper harness, replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

25 |

1. Repair the short to ground in CKT 833.
2. If the short to ground is found in the right front wheel speed sensor jumper harness, replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

26 |

1. Repair the short to ground in CKT 872.
2. If the short to ground is found in the right front wheel speed sensor jumper harness, replace the right front wheel speed jumper harness.

Is the repair complete?

--

Go to Diagnostic System Check

--

27 | Replace all of the terminals and the connectors that exhibit signs of poor terminal contact, corrosion, or damaged terminals. Is the repair complete? | -- | Go to Diagnostic System Check | --
28 | Replace the right front wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | --
29 | Replace the right front wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | --
30 | Replace the EBCM/EBTCM. Refer to Electronic Brake and Traction Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | --
31 | The malfunction is intermittent or not present at this time.

1. Inspect all of the connectors and the harnesses for damage that may cause the following conditions:

- | An open or a high resistance

- | A short to ground

- | A short to voltage

2. The jumper harness must be replaced if the jumper harness is damaged.

Is the repair complete?

--

Go to Diagnostic System Check

Go to Diagnostic Aids