Toyota Tacoma (2015-2018) Service Manual: Low Output Signal of Front Speed Sensor RH (Test Mode DTC) (C1271,C1272,C1401,C1402)
DESCRIPTION
The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU (master cylinder solenoid). These signals are used for brake control.
The speed sensor rotors have rows of alternating N and S magnetic poles and their magnetic fields change when the rotors turn.
Each speed sensor detects that magnetic change and sends a pulse signal to the skid control ECU (master cylinder solenoid).
|
DTC Code |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
C1271 C1272 |
Stored only during test mode. |
|
|
C1401 C1402 |
One of the following conditions is met:
|
|
HINT:
- DTCs C1401 and C1271 are for the front speed sensor RH.
- DTCs C1402 and C1272 are for the front speed sensor LH.
CAUTION / NOTICE / HINT
NOTICE:
Check the speed sensor signal after cleaning or replacement (See page
.gif)
).
PROCEDURE
|
1. |
CHECK FRONT SPEED SENSOR INSTALLATION |
(a) Turn the ignition switch off.
|
(b) Check the speed sensor installation. OK: There is no clearance between the sensor and the front steering knuckle. The installation bolt is tightened properly. Torque 8.3 N*m (85 kgf*cm, 73 in.*lbf) Text in Illustration
|
|
| NG | .gif) |
INSTALL FRONT SPEED SENSOR CORRECTLY |
|
.gif)
|
2. |
INSPECT FRONT SPEED SENSOR TIP |
(a) Remove the front speed sensor (See page
).
(b) Check the speed sensor tip.
OK:
No scratches, oil, or foreign matter on the sensor tip.
NOTICE:
If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.
| NG | |
CLEAN OR REPLACE FRONT SPEED SENSOR |
|
|
3. |
INSPECT FRONT SPEED SENSOR ROTOR |
(a) Remove the front axle with ABS rotor bearing assembly (See page
).
(b) Check the speed sensor rotor.
OK:
No scratches, oil, or foreign matter on the rotors.
HINT:
The front speed sensor rotor is incorporated into the front axle with ABS rotor bearing assembly.
If the front speed sensor rotor needs to be replaced, replace it together with the front axle with ABS rotor bearing assembly.
| NG | |
CLEAN OR REPLACE FRONT AXLE WITH ABS ROTOR BEARING ASSEMBLY |
|
|
4. |
READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR) |
(a) Turn the ignition switch off.
(b) Connect the Techstream to the DLC3.
(c) Start the engine.
(d) Turn the Techstream on.
(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.
ABS/VSC/TRAC|
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) |
Actual wheel speed |
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) |
Actual wheel speed |
No large fluctuations when driving at a constant speed. |
(f) Check that there is no difference between the speed value output from the speed sensor displayed on the Techstream and the speed value displayed on the speedometer when driving the vehicle.
HINT:
Factors that affect the indicated vehicle speed include tire size, tire inflation
and tire wear. The speed indicated on the speedometer has an allowable margin of
error. This can be tested using a speedometer tester (calibrated chassis dynamometer).
For details about testing and the margin of error, refer to the reference chart
(See page ).
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).
| OK | |
USE SIMULATION METHOD TO CHECK |
|
|
5. |
REPLACE FRONT SPEED SENSOR |
(a) Replace the front speed sensor (See page
).
|
|
6. |
RECONFIRM DTC |
(a) Clear the DTCs (See page
).
(b) Turn the ignition switch off.
(c) Start the engine.
(d) Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.
(e) Check if the same DTC is output (See page
).
|
Result |
Proceed to |
|---|---|
|
DTCs C1401 and C1402 are not output |
A |
|
DTCs C1401 and/or C1402 are output |
B |
| A | |
END |
| B | |
REPLACE FRONT AXLE WITH ABS ROTOR BEARING ASSEMBLY |
Transfer L4 Position Switch Circuit (C1268)
DESCRIPTION
A-TRAC is activated if wheel skid is detected while the transfer is in the L4
position.
DTC Code
DTC Detecting Condition
Trouble Areas
...
Low Output Signal of Rear Speed Sensor RH (Test Mode DTC) (C1273,C1274,C1403,C1404)
DESCRIPTION
Refer to DTCs C1401 and C1402 (See page ).
DTC Code
DTC Detection Condition
Trouble Area
C1273
C1274
Stored only during t ...
Other materials:
Front Differential Oil Temperature Sensor Circuit Low (P17C7)
DESCRIPTION
This DTC is output when a short to ground in the oil temperature sensor is detected.
DTC No.
Detection Item
DTC Detection Condition
Trouble Area
P17C7
Front Differential Oil Temperature Sensor Circuit Low
...
Yaw Rate Sensor Circuit (C1AA4,C1AA5)
DESCRIPTION
The forward recognition camera receives vehicle stability signals from the yaw
rate and acceleration sensor (airbag sensor assembly). If the yaw rate and acceleration
sensor (airbag sensor assembly) detects an abnormal yaw rate sensor signal or yaw
rate sensor assembly power suppl ...
Removal
REMOVAL
PROCEDURE
1. REMOVE SHIFT LEVER KNOB SUB-ASSEMBLY (for Automatic Transmission)
(a) Using a molding remover A, disengage the 2 claws to separate the
shifting hole cover sub-assembly.
(b) Rotate the shift lever knob sub-as ...
