Circuit Description
The Park/Neutral Position (PNP) switch is part of the neutral start switch. The PNP switch contacts close the input circuit to the PCM to ground when the transaxle manual shaft is in the park or neutral position. The PNP switch is open when a transaxle drive range is selected. The PCM uses PNP information to perform the following functions:
| • | Control idle speed using the IAC. |
| • | Vehicle Speed Sensor (VSS)/Transaxle Output Speed Sensor (TOSS) diagnostics. |
| • | IC spark advance. |
The PCM supplies 12 volts to the PNP input circuit through a current limiting resistor. The PCM senses a closed switch (Park or Neutral selected) when the voltage on the PNP input circuit drops below 1 volt.
Conditions for Setting the DTC
| • | Signal on the PNP circuit indicates an open PNP switch during 3 consecutive startups. |
OR
| • | No Transaxle Range Switch DTC set. |
| • | Signal on the PNP circuit is grounded. |
| • | Transaxle is operating in 3rd or 4th gear. |
| • | TCC is locked |
| • | Above conditions present for longer than 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear Info function. |
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for the following conditions:
| • | Misadjusted PNP switch. |
| Refer to 4T60-E Automatic Transaxle On-Vehicle Service . |
| • | Poor connection. |
| Inspect the PCM and PNP Switch harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PNP switch 7 way connector, turn the ignition ON and observe a voltmeter connected to the PNP circuit at the PNP switch harness connector while moving connectors and wiring harnesses related to the PNP switch. A change in voltage will indicate the location of the malfunction. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic System Check performed? | -- | ||||||||
2 |
Does the scan tool indicate that Park/Neutral is selected? | -- | ||||||||
3 |
Does the scan tool indicate that Park/Neutral is selected? | -- | ||||||||
4 | Observe Park/Neutral Position displayed on the scan tool while selecting D1, D2, D3, D4 and Reverse transaxle positions. Does the scan tool indicate that park or neutral is selected in any of the above positions? | -- | Refer to Diagnostic Aids | |||||||
5 |
Is the test light ON in Park and Neutral? | -- | ||||||||
6 |
Does the scan tool indicate Park/Neutral? | -- | ||||||||
7 |
Was a problem found? | -- | ||||||||
8 | Attempt to adjust the transaxle range switch. Refer to 4T60-E Transaxle On-Vehicle Service in section 7. Can the transaxle range switch be adjusted so that the scan tool displays Park/Neutral Position correctly? | -- | ||||||||
9 |
Was a problem found? | -- | ||||||||
10 |
Was a problem found? | -- | ||||||||
11 | Replace the transaxle range switch. Refer to 4T60-E Transaxle On-Vehicle Service in section 7. Is action complete? | -- | -- | |||||||
12 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is action complete? | -- | -- | |||||||
13 |
Does the scan tool indicate the correct park/neutral status in each gear position? | -- | System OK |
