Toyota Tacoma 2015-2018 Service Manual: Rear Differential Lock Position SW Stuck OFF (P17BB)

Toyota Tacoma 2015-2018 Service Manual / Differential / Differential System(w/ Rear Differential Lock) / Rear Differential Lock Position SW Stuck OFF (P17BB)

DESCRIPTION

This DTC is output when an OFF malfunction of the differential lock indicator switch is detected.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
P17BB	Rear Differential Lock Position SW Stuck OFF	Diagnosis Condition: With ignition switch turned to ON, rear differential is locked (differential lock coil operating) Malfunction Status: With vehicle speed 5 km/h or higher, differential lock indicator switch is stuck OFF Malfunction Time: 3 seconds or more Other: 1 trip detection logic	Wire harness and connector 4 wheel drive control ECU Differential lock indicator switch

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

for 4WD:

When the rear differential lock position switch (transfer indicator switch) is stuck OFF, if the transfer is set to 2WD, the vehicle is stopped and the ignition switch is turned from off to ON, the system returns to normal and this DTC is stored as a past DTC.

If the transfer is set to L4 again, the rear differential is locked and the vehicle is driven at 5 km/h or more, this DTC is output again.

for 2WD:

When the rear differential lock position switch (transfer indicator switch) is stuck OFF, the vehicle is stopped and the ignition switch is turned from off to ON, the system returns to normal and this DTC is stored as a past DTC.

If the rear differential is locked and the vehicle is driven at 5 km/h or more, this DTC is output again.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (4 WHEEL DRIVE CONTROL ECU - DIFFERENTIAL LOCK INDICATOR SWITCH)

(a) Disconnect the F13 4 wheel drive control ECU connector.

(b) Disconnect the T13 differential lock indicator switch connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F13-12 (SLS) - T13-2 (RLY2)	Always	Below 1 Ω
T13-1 (GND) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	CHECK 4 WHEEL DRIVE CONTROL ECU (ECU OUTPUT VOLTAGE)

(a) Disconnect the differential lock indicator switch connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
T13-2 (RLY2) - Body ground	Ignition switch ON	10 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Differential Lock Indicator Switch)

REPLACE 4 WHEEL DRIVE CONTROL ECU

3.	CHECK DIFFERENTIAL LOCK INDICATOR SWITCH

(a) for Automatic Transmission:

Move the shift lever to N.

for Manual Transmission:

Move the shift lever to neutral.

(b) for 4WD:

Switch the transfer position switch to L4.

(d) Release the parking brake.

(e) Operate the differential lock switch to switch to locked.

HINT:

The rear differential lock indicator light continues to blink.

(f) Rotate one rear wheel in both directions and set the rear differential to the locked condition.

HINT:

When the rear differential is locked, rotating one rear wheel causes the other rear wheel to rotate in the same direction.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
F13-12 (SLS) - Body ground	Rear differential in locked condition	Below 1.5 V

Text in Illustration

*a	Component with harness connected (4 Wheel Drive Control ECU)

REPLACE 4 WHEEL DRIVE CONTROL ECU

REPLACE DIFFERENTIAL LOCK INDICATOR SWITCH

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