Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: 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

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.

(c) Disconnect the D28 differential lock coil 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

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

2.

INSPECT DIFFERENTIAL LOCK COIL

(a) Turn the ignition switch off.

(b) Disconnect the D28 differential lock coil connector.

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

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

OK

REPLACE 4 WHEEL DRIVE CONTROL ECU

NG

REPLACE DIFFERENTIAL LOCK COIL

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