P040

Diagnostic Trouble Code Chart P040:

Idle Speed Control/Power Steering Pressure Switch Circuit:

CIRCUIT DESCRIPTION
The Power Steering Pressure (PSP) switch is a normally closed switch which opens when power steering pressure exceeds 3103 to 4482 kPa (450 to 650 psi). The PSP switch closes again when pressure drops below 689 to 3103 kPa (100 to 450 psi).

This diagnostic test monitors the power steering pressure switch. When a load is placed on the power steering such as full lock, the switch opens. Code P040 sets when the vehicle is above 45 mph and the power steering pressure switch is open.

TEST CONDITIONS
1. Engine running.
2. Vehicle speed 45 mph or greater.

FAILURE CONDITION
Power steering pressure switch open for 60 seconds.

ACTION TAKEN
1. Turns "ON" the "Service Vehicle Soon" message.

NOTES ON FAULT TREE
1. Check if PI85 will cycle from "HI" to "LO" to "HI." If PI85 stays "LO," there is an open or short to ground in the circuitry. If PI85 stays "HI," there is a short to voltage in the circuitry.
2. Checking if CKT 495 is shorted to voltage or if the power steering pressure is faulty.
3. Checking if CKT 741 or fuse "D1" is open.
4. Checking if the power steering pressure switch is open.
5. Checking if CKT 495 is open or if Powertrain Control Module (PCM) is faulty.