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Last Modified: 11-27-2007 1.6 C
Service Category: Vehicle Interior Section: Theft Deterrent/Keyless Entry
Model Year: 2008 Model: LX570 Doc ID: RM000000TUF01WX
Title: THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM: DESCRIPTION (2008 LX570)

DTC

B278A

Short to GND in Immobiliser System Power Source Circuit

DESCRIPTION

This DTC is stored when the engine switch power source supply line is open or shorted.

DTC Code

DTC Detection Condition

Trouble Area

B278A

The engine switch power source supply line is open or shorted.
  • Harness or connector
  • Engine switch
  • Certification ECU (smart key ECU assembly)

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU) - ENGINE SWITCH)


(a) Disconnect the E29 ECU connector.

(b) Disconnect the E18 switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

E29-30 (VC5) - E18-14 (VC5)

Always

Below 1 Ω

E29-40 (AGND) - E18-8 (AGND)

E29-30 (VC5) or E18-14 (VC5) - Body ground

Always

10 kΩ or higher

E29-40 (AGND) or E18-8 (AGND) - Body ground
OK

2.

REPLACE ENGINE SWITCH

(a) Temporarily replace the engine switch with a new one 3UR-FE STARTING: ENGINE SWITCH: REMOVAL (2008 LX570) .

NEXT

3.

CLEAR DTC

(a) Clear the DTCs THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

NEXT

4.

CHECK FOR DTC

(a) Check for DTCs THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM: DTC CHECK / CLEAR (2008 LX570) .

OK:

DTC B278A is not output.

OK