Test Ff: Power Steering Pressure Switch: Testing
- 1) For KOEO & KOER Only DTC P1650: Check PSP PID
DTC P1650 indicates PSP signal input to PCM was high when retrieved during KOEO on-demand self-test. DTC P1650 indicates PSP signal input to PCM did not change state when retrieved during KOER on-demand self-test. Possible causes for these faults are:- Steering Wheel Was Not Turned During KOER ON-DEMAND SELF-TEST
- Faulty PSP Switch/Shorting Bar Damage
- SIG RTN Circuit Open
- PSP Circuit Open Or Shorted To SIG RTN
- Faulty Powertrain Control Module (PCM)
Connect scan tool to Data Link Connector (DLC). Start engine and allow to idle. Using scan tool, access PSP PID from PID/DATA MONITOR & RECORD menu. Observe PSP PID and turn steering wheel to the left, then to the right. If PSP PID value does not indicate a change, go to next step. If PSP PID value indicates a change, go to step 10).
- 2) Check For PSP Circuits To PSP Switch For Cycling
Turn ignition switch to OFF position. Remove shorting bar or disconnect connector from PSP switch. Install a jumper wire between PSP switch harness connector terminals. Start engine and allow to idle. Record PSP PID value. Disconnect jumper wire and again record PSP PID value. If PSP PID value changed from low to high, replace PSP switch. If PSP PID value did not change as specified, go to next step (Focus), or go to step 4) (all others). - 3) Check For Open GND Circuit To PSP Switch
Turn ignition switch to OFF position. Using a DVOM, measure resistance of PSP circuit between PSP sensor harness connector and chassis ground. See Figure. If resistance measurement is less than 5 ohms, go to next step. If resistance measurement is 5 ohms or more, repair open in PSP circuit. - 4) Check PSP & SIG RTN Circuits For Open In Harness
Ensure ignition switch is in OFF position. Disconnect PCM connector(s). On all models, use a DVOM and measure resistance of PSP circuit between PCM harness connector and PSP switch harness connector. On all models except Focus, use a DVOM and measure resistance of SIG RTN circuit between PCM harness connector and PSP switch harness connector. See Figure or Figure . If all resistance measurements are less than 5 ohms, go to next step. If any resistance measurement is 5 ohms or more, repair open in PSP or SIG RTN circuit. - 5) Check PSP Circuit For Short To SIG RTN Or Ground In Harness
On all models, use a DVOM and measure resistance between PSP circuit at PSP switch harness connector and chassis ground. On all models except Focus, use a DVOM and measure resistance between PSP and SIG RTN circuits at PSP switch harness connector. See Figure or Figure . If all resistance measurements are more than 10 k/ohms, replace PCM. If either resistance measurement is 10 k/ohms or less, repair short to ground or between affected circuits.NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 5) to step 10). No test procedures have been omitted. - 10) For Continuous Memory Only DTC P1651: Check PSP Circuits For Intermittent
Continuous Memory DTC P1651 is set when PCM does not detect a change in PSP signal input when PCM is detecting a calibratable number of speed transitions. Possible causes for these faults are:- Vehicle Towed With Engine Running
- Power Steering Hydraulic Concern Repaired, But DTC Not Cleared
- Faulty PSP Switch/Shorting Bar Damage
- SIG RTN Circuit Open
- PSP Circuit Open Or Shorted To SIG RTN
- Faulty Powertrain Control Module (PCM)
Ensure scan tool is connected to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access PSP V PID from PID/DATA MONITOR & RECORD menu. While observing PSP V PID, lightly tap on PSP switch and shake, wiggle and bend PSP, SIG RTN or GND circuits between PSP sensor and PCM to simulate road shock. Disconnect PSP switch. Check PSP circuit for short to ground. While observing PSP V PID, wiggle and bend PSP, SIG RTN or GND circuits between PSP sensor and PCM. A fault is indicated by a sudden change of PSP V PID value. If fault is indicated, turn ignition switch to OFF position, isolate area and repair as necessary. If no fault is indicated, turn ignition switch to OFF position, reconnect PSP switch connector and go to TEST Z, step 1) .