Lexus ES: ABS Malfunction (C1296)
DESCRIPTION
If a malfunction in the speed sensor signal circuit or yaw rate and acceleration sensor (airbag ECU assembly) circuit occurs, the 4WD ECU assembly will output this DTC.
The airbag ECU assembly has a built-in yaw rate and acceleration sensor.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| C1296 | ABS Malfunction | When one of the following conditions is met:
|
|
| Vehicle Condition | |||
|---|---|---|---|
| Pattern 1 | Pattern 2 | ||
| Diagnosis Condition | When communication occurs with the skid control ECU (brake actuator assembly) | ○ | ○ |
| Malfunction Status | Wheel speed sensor malfunction is received | ○ | - |
| Yaw rate and acceleration sensor (airbag ECU assembly) malfunction is received | - | ○ | |
| Detection Time | - | - | |
| Number of Trips | 1 trip | 1 trip | |
HINT:
DTC will be output when conditions for either of the patterns in the table above is met.
WIRING DIAGRAM
PROCEDURE
| 1. | CHECK FOR DTC (ELECTRONICALLY CONTROLLED BRAKE SYSTEM) |
(a) Clear the DTC.
Chassis > Brake/EPB > Clear DTCs(b) Turn the engine switch off.
(c) Turn the engine switch on (IG) again.
(d) Drive the vehicle, accelerate to a speed of 20 km/h (12 mph) or more, and check if the speed sensor DTC (electronically controlled brake system DTC) is output.
Chassis > Brake/EPB > Trouble Codes| Result | Proceed to |
|---|---|
| Electronically controlled brake system DTC (speed sensor or acceleration sensor DTC) is not output | A |
| Electronically controlled brake system DTC (speed sensor or acceleration sensor DTC) is output | B |
HINT:
When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before repairing each corresponding sensor.
| B | .gif) | REPAIR CIRCUIT INDICATED BY OUTPUT CODE (ELECTRONICALLY CONTROLLED BRAKE SYSTEM) |
|
.gif)
| 2. | READ VALUE USING TECHSTREAM (WHEEL SPEED) |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Chassis / Four Wheel Drive / Data List.
(e) Read the value displayed on the Techstream.
Chassis > Four Wheel Drive > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| FR Wheel Speed | Front wheel speed sensor RH reading | Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) | 0 km/h (0 mph): Vehicle stopped | No large fluctuations when driving at a constant speed. |
| FL Wheel Speed | Front wheel speed sensor LH reading | Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) | 0 km/h (0 mph): Vehicle stopped | No large fluctuations when driving at a constant speed. |
| RR Wheel Speed | Rear wheel speed sensor RH reading | Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) | 0 km/h (0 mph): Vehicle stopped | No large fluctuations when driving at a constant speed. |
| RL Wheel Speed | Rear wheel speed sensor LH reading | Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) | 0 km/h (0 mph): Vehicle stopped | No large fluctuations when driving at a constant speed. |
| Tester Display |
|---|
| FR Wheel Speed |
| FL Wheel Speed |
| RR Wheel Speed |
| RL Wheel Speed |
OK:
The speed value output from the speed sensor displayed on the Techstream is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).
| NG | | GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) |
|
| 3. | READ VALUE USING TECHSTREAM (FORWARD AND REARWARD G) |
(a) Enter the following menus: Chassis / Four Wheel Drive / Data List.
(b) Read the value displayed on the Techstream.
Chassis > Four Wheel Drive > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Forward and Rearward G | Forward and Rearward G | Min.: -25.10 m/s2 Max.: 24.90 m/s2 | Approximately 0 +/-0.13 m/s2 while stationary | Changes in proportion with acceleration during acceleration/deceleration. |
| Tester Display |
|---|
| Forward and Rearward G |
OK:
The yaw rate and acceleration sensor (airbag ECU assembly) output value is normal.
| OK | | REPLACE 4WD ECU ASSEMBLY |
.gif)
| NG | | GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) |
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