Brake Control Dynamic Control Systems. Dtc C1273 Low Output Signal Of Rear Speed Sensor Rh (Test Mode Dtc)

DTCs C1273 to C1278 will be cleared when the speed sensor sends a vehicle speed signal or when Test Mode ends. DTCs from C1273 to C1278 are output only in Test Mode.

DTC Code	DTC Detection Condition	Trouble Area
C1273 C1274	Detected only during Test Mode.	Rear speed sensor RH/LH Sensor installation Speed sensor rotor
C1277 C1278	Detected only during Test Mode.	Speed sensor rotor

HINT:

DTCs C1273 and C1277 are for the rear speed sensor RH.
DTCs C1274 and C1278 are for the rear speed sensor LH.

WIRING DIAGRAM

Refer to DTCs C1403 and C1404 (Link).

INSPECTION PROCEDURE

NOTICE:

When replacing the brake actuator assembly, perform zero point calibration (COROLLA_ZRE142 RM000000XHR08KX.html).

1.CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to the DTC (COROLLA_ZRE142 RM000000XHS0CJX.html).

ABS/VSC/TRAC
Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
RR Speed Open	RR speed sensor open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-
RL Speed Open	RL speed sensor open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-

Result:

Result	Proceed to
There are momentary interruptions	A
There are no momentary interruptions	B
There is a constant open circuit	C

HINT:

Perform the above inspection before removing the sensor and connector.

Go to step 4

Go to step 6

A

2.REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - REAR SPEED SENSOR)

Turn the ignition switch off.

Repair or replace the harness or connector.

Check for any momentary interruption between the skid control ECU and the rear speed sensor (COROLLA_ZRE142 RM000000XHS0CJX.html).

Check that there are no momentary interruptions.

NEXT

3.PERFORM TEST MODE (SIGNAL CHECK)

Turn the ignition switch off.

Perform the sensor check in the Test Mode procedure (COROLLA_ZRE142 RM000000XHT0ATX.html).
OK:
All Test Mode DTCs are cleared.

Go to step 4

END

4.READ VALUE USING TECHSTREAM (REAR SPEED SENSOR)

Turn the ignition switch off.

Connect the Techstream to the DLC3.

Start the engine.

Select the Data List on the Techstream (COROLLA_ZRE142 RM000000XHW0BYX.html).

ABS/VSC/TRAC
Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
RR Wheel Speed	RR wheel speed sensor reading / min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)	Actual wheel speed	Similar speed as indicated on speedometer
RL Wheel Speed	RL wheel speed sensor reading / min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)	Actual wheel speed	Similar speed as indicated on speedometer

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, see the reference chart (COROLLA_ZRE142 RM0000014WB08AX.html).
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).

Go to step 6

OK

5.PERFORM TEST MODE (SIGNAL CHECK)

Turn the ignition switch off.

Perform the sensor check in the Test Mode procedure (COROLLA_ZRE142 RM000000XHT0ATX.html).
OK:
All Test Mode DTCs are cleared.

Go to step 6

CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (COROLLA_ZRE142 RM000000XHP0EKX.html)

6.CHECK REAR SPEED SENSOR INSTALLATION

Corolla. Zre142 Aze141.Brake Control Dynamic Control Systems.Anti-Lock Brake System.
Dtc
C1273 Low Output Signal Of Rear Speed Sensor Rh (Test Mode Dtc)

Turn the ignition switch off.

Check the speed sensor installation.
OK:
There is no clearance between the sensor and the rear axle carrier.

INSTALL REAR SPEED SENSOR CORRECTLY (COROLLA_ZRE142 RM000002VP902UX.html)

OK

7.CHECK HARNESS AND CONNECTOR (SKID CONTROL SENSOR WIRE)

Make sure that there is no looseness at the locking part and the connecting part of the connectors.

Disconnect the skid control sensor wire.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH:

Tester Connection	Condition	Specified Condition
W1 ("A"-2) - W1 ("B"-1)	Always	Below 1 Ω
W1 ("A"-2) - W1 ("B"-2)	Always	10 kΩ or higher
W1 ("A"-2) - Body ground	Always	10 kΩ or higher
W1 ("A"-1) - W1 ("B"-2)	Always	Below 1 Ω
W1 ("A"-1) - W1 ("B"-1)	Always	10 kΩ or higher
W1 ("A"-1) - Body ground	Always	10 kΩ or higher

for LH:

Tester Connection	Condition	Specified Condition
V1 ("A"-2) - V1 ("B"-1)	Always	Below 1 Ω
V1 ("A"-2) - V1 ("B"-2)	Always	10 kΩ or higher
V1 ("A"-2) - Body ground	Always	10 kΩ or higher
V1 ("A"-1) - V1 ("B"-2)	Always	Below 1 Ω
V1 ("A"-1) - V1 ("B"-1)	Always	10 kΩ or higher
V1 ("A"-1) - Body ground	Always	10 kΩ or higher

NOTICE:

Check the speed sensor signal after replacement (COROLLA_ZRE142 RM000000XHT0ATX.html).

REPLACE SKID CONTROL SENSOR WIRE

OK

8.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - REAR SPEED SENSOR)

Reconnect the skid control sensor wire.

Make sure that there is no looseness at the locking part and the connecting part of the connectors.

Disconnect the skid control ECU connector and the rear speed sensor connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH:

Tester Connection	Condition	Specified Condition
A66-17 (RR+) - W1-2 (RR+)	Always	Below 1 Ω
A66-17 (RR+) - Body ground	Always	10 kΩ or higher
A66-16 (RR-) - W1-1 (RR-)	Always	Below 1 Ω
A66-16 (RR-) - Body ground	Always	10 kΩ or higher

for LH:

Tester Connection	Condition	Specified Condition
A66-5 (RL+) - V1-2 (RL+)	Always	Below 1 Ω
A66-5 (RL+) - Body ground	Always	10 kΩ or higher
A66-4 (RL-) - V1-1 (RL-)	Always	Below 1 Ω
A66-4 (RL-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

9.INSPECT SKID CONTROL ECU (SENSOR INPUT)

Reconnect the skid control ECU connector.

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage:
for RH:
Tester Connection
Switch Condition
Specified Condition
W1-2 (RR+) - Body ground
Ignition switch ON
8 to 14 V
for LH:
Tester Connection
Switch Condition
Specified Condition
V1-2 (RL+) - Body ground
Ignition switch ON
8 to 14 V

REPLACE BRAKE ACTUATOR ASSEMBLY (COROLLA_ZRE142 RM000003CZU00MX.html)

OK

10.PERFORM TEST MODE (SIGNAL CHECK)

Turn the ignition switch off.

Perform the sensor check in the Test Mode procedure (COROLLA_ZRE142 RM000000XHT0ATX.html).
OK:
All Test Mode DTCs are cleared.

Go to step 11

CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (COROLLA_ZRE142 RM000000XHP0EKX.html)

11.REPLACE REAR SPEED SENSOR AND REAR SPEED SENSOR ROTOR

Turn the ignition switch off.

Replace the rear speed sensor and the rear axle hub and bearing assembly (rear speed sensor rotor) (COROLLA_ZRE142 RM000002VPC02SX.html).
HINT:
The rear speed sensor rotor is incorporated into the rear axle hub and bearing assembly.
If the rear speed sensor rotor needs to be replaced, replace it together with the rear axle hub and bearing assembly with rear speed sensor.
NOTICE:
Check the speed sensor signal after replacement (COROLLA_ZRE142 RM000000XHT0ATX.html).

NEXT

12.PERFORM TEST MODE (SIGNAL CHECK)

Perform the sensor check in the Test Mode procedure (COROLLA_ZRE142 RM000000XHT0ATX.html).
OK:
All Test Mode DTCs are cleared.

REPLACE BRAKE ACTUATOR ASSEMBLY (COROLLA_ZRE142 RM000003CZU00MX.html)

END

Tester Connection	Switch Condition	Specified Condition
W1-2 (RR+) - Body ground	Ignition switch ON	8 to 14 V