DTC 51

Data Trouble Code No. 51 - Switch Condition Signal

Detecting Condition

3 seconds or more after engine starts with IDL 1 Switch OFF.
or
Automatic Transmission Park / Neutral Switch OFF (PNP)
or
Air conditioning switched ON

Trouble Area

- Throttle Position Sensor IDL circuit.
- Accelerator pedal and cable.
- Park / neutral Position Switch circuit.
- Air Conditioning Switch circuit.
- Engine Control Module.

Malfunction Indicator Lamp

Normal Mode N.A.
Test Mode Off

Code 51 Description:

Circuit Description

- Park/Neutral Position Switch Signal
The engine control module uses the signals from the Park/neutral position switch to determine whether the transmission is in park or neutral, or in some other gear.

- Air Conditioning Switch Signal
The engine control module uses the output from the air conditioning switch to determine whether or not the air conditioning is operating so that it can increase the idling speed of the engine if necessary.

- Throttle Position Sensor IDL Signal
The IDL contacts are mounted in the throttle position sensor, and detects the idle condition.

HINT: In this circuit, diagnosis can only be made in the test mode.

Code 51 Circuit Diagram:

Circuit Diagram

Code 51 Diagnostic Procedure:

Diagnostic Chart

Code 51 Inspection Procedure:

Code 51 Inspection Procedure Part 2:

Diagnostic Chart