Toyota Tacoma 2015-2018 Service Manual: 4WD ECU Malfunction (P163B)

Toyota Tacoma 2015-2018 Service Manual / Differential / Differential System(w/ Rear Differential Lock) / 4WD ECU Malfunction (P163B)

DESCRIPTION

This DTC is output when a malfunction is detected in the 4 wheel drive control ECU internal circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
P163B	4WD ECU Malfunction	Diagnosis Condition: Directly after ignition switch is turned to ON, or when switching operations are performed with ignition switch turned to ON Malfunction Status: 4 wheel drive control ECU internal circuit malfunction Malfunction Time: 0.5 seconds or more (directly after the ignition switch is turned to ON, 0.05 seconds or more) Other: 1 trip detection logic	Wire harness and connector Differential lock coil 4 wheel drive control ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

4WD specification:

If P163B is detected, troubleshoot the TOUCH SELECT 2-4 AND HIGH-LOW system first.

PROCEDURE

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

(a) Turn the ignition switch off.

(b) Disconnect the F12 4 wheel drive control ECU connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F12-1 (SL+) - D28-2 (SL+)	Always	Below 1 Ω
F12-5 (SL-) - D28-1 (SL-)	Always	Below 1 Ω
F12-1 (SL+) or D28-2 (SL+) - Body ground	Always	10 kΩ or higher
F12-5 (SL-) or D28-1 (SL-) - Body ground	Always	10 kΩ or higher

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F12-1 (SL+) or D28-2 (SL+) - Body ground	Ignition switch ON	Below 1 V
F12-5 (SL-) or D28-1 (SL-) - Body ground	Ignition switch ON	Below 1 V

REPAIR OR REPLACE HARNESS AND CONNECTOR

2.	INSPECT DIFFERENTIAL LOCK COIL

(a) Turn the ignition switch off.

(b) Disconnect the D28 differential lock coil connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
1 (SL-) - 2 (SL+)	Always	2.65 to 2.95 Ω
1 (SL-) or 2 (SL+) - Body ground	Always	10 kΩ or higher

Text in Illustration

*a	Component without harness connected (Differential Lock Coil)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
1 (SL-) or 2 (SL+) - Body ground	Ignition switch ON	Below 1 V

REPLACE 4 WHEEL DRIVE CONTROL ECU

REPLACE DIFFERENTIAL LOCK COIL

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