FF: Power Steering Pressure (PSP) Switch

FF: Introduction See: FF: Power Steering Pressure (PSP) Switch - Introduction

FF1 DTC P1650: VERIFY ELECTRICAL FUNCTION

Note: If P1650 was received in Key On Engine Running Self-Test, verify that the steering wheel was turned at least one half turn within 20 seconds of starting test.

• Connect scan tool.
• Key on, engine running.
• Access PSP PID (PSP V PID for Taurus/Sable).
• Turn the steering wheel back and forth.

Does the PSP PID (or PSP V PID) indicate a change?
Yes

• GO to FF10

.

No

• KEY OFF. GO to FF2

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FF2 CHECK FOR PSP SWITCH CYCLING

• Disconnect PSP switch or remove the shorting bar.
• Install a jumper wire across the PSP switch harness connector.
• Key on, engine off.
• Record the PID reading.
• Remove the jumper wire and record the PID reading.

Does the PSP PID change from high to low (or PSP V PID change from less than 1.0 volt to greater than 8 volts)?
Yes

• REPLACE the PSP switch or shorting bar.

No

• KEY OFF. GO to FF3

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FF3 CHECK PSP CIRCUIT FOR OPEN IN HARNESS

Note: Refer to the PCM connector pin numbers at the beginning of the pinpoint test.

• Disconnect PCM.
• Measure resistance of PSP circuit between PCM harness connector pin and PSP switch harness connector.
• Measure resistance of SIG RTN circuit between PCM harness connector pin and PSP switch harness connector.

Is each resistance less than 5.0 ohms?
Yes

• GO to FF4

.

No

• REPAIR open circuit.

FF4 CHECK PSP CIRCUIT FOR SHORT TO SIG RTN OR GROUND IN HARNESS

• Measure resistance between PSP signal and SIG RTN at PSP switch harness connector.
• Measure resistance between PSP signal at PSP switch harness connector and chassis ground.

Is either resistance less than 10,000 ohms?
Yes

• REPAIR short circuit.

No

• REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

FF10 DTC P1651: CHECK PSP CIRCUITS FOR INTERMITTENT CONCERNS

Note: Be aware that P1651 could be set if the vehicle is towed with the engine running, or if a power steering hydraulic concern was present.

• Key on, engine off.
• Access PSP V PID.
• Check for open circuits while performing the following (a fault will be indicated by a sudden change in the PSP V PID):
• Shake, wiggle, bend the PSP and SIG RTN circuits between the PSP switch and the PCM.
• Lightly tap on the PSP switch (to simulate road shock).
• Disconnect PSP switch.
• Check PSP circuit for short to ground while performing the following (a fault will be indicated by a sudden change in the PSP V PID voltage):
• Shake, wiggle, bend the PSP circuit between the PSP switch and the PCM.

Is a fault indicated?
Yes

• KEY OFF. ISOLATE fault and REPAIR as necessary.

No

• KEY OFF. RECONNECT PSP switch. Unable to duplicate or identify

fault at this time. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test
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