Chart C-1A Power Steering Pressure (PSP) Switch Check

Chart C-1A:

Power Steering Pressure Switch Circuit:

CIRCUIT DESCRIPTION
The Power Steering Pressure (PSP) switch is a normally closed switch, which opens when the power steering pressure exceeds 3102 to 4481 kPa (450 to 650 psi). The PSP switch closes again when pressure drops below 689 to 3102 kPa (100 to 450 psi). When a load is placed on the power steering such as full lock, the PSP switch opens. This diagnostic test checks for a power steering pressure switch, Powertrain Control Module (PCM) circuit problem. This is done by comparing the PSP switch reading to a PCM diagnostic software valve which should not be attained if no problem exists. Also this diagnostic checks for power steering load present.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. With the Tech 1 scan tool installed, check for a DTC 40. If no DTC is set, refer to DTC 40. If no DTC is set, current or history (check if PCM has stored a snapshot). Refer to Tech 1 snapshot list. PCM Snapshot Data
2. Check if a power steering load is present.
3. Check to determine if CKT 495 is shorted to ground.
4. This should simulate a closed switch.

DIAGNOSTIC AIDS
If the customer complaint has been stalling, refer to Diagnosis by Symptom / Rough, Unstable or Incorrect Idle, Stalling. Rough, Unstable, or Incorrect Idle, Stalling
An intermittent condition should be road tested. Vehicle speed must be 45 mph or greater for the diagnostic test to run.