Refer to Electrical Schematic Diagrams for wiring view.
Circuit Description
This vehicle uses an electronic gear indicator display. There are four inputs which are switches to ground that each have a unique switch pattern. All four of these inputs are housed and operate together in the Transaxle Range Switch. The PCM uses the combination of the switch patterns to determine the gear selected by the driver. This information is then sent by serial data to the IPC for gear indicator display. When the Test Conditions are true this test compares the gear indicated by the Transaxle Range Switch to the gear selected from the Transmission Fluid Pressure Manual Valve Position Switch (pressure switch). If the gear indicated is not the same for both, this DTC is set.
Conditions for Setting the DTC
Test Conditions
| • | Engine running continously for 5 seconds. |
| • | Ignition voltage is between 10 and 16 volts. |
| • | Transaxle Range (select lever) switch does not indicate an illegal position. |
| • | Transmission Fluid Pressure Manual Valve Position Switch (pressure switch) does not indicate an illegal position. |
| • | DTC P1810 has ran and passed. |
Failure Condition
The Transaxle Range switch and the Transmission Fluid Pressure Manual Valve Position Switch (pressure switch) indicate different gears for at least 7.8 seconds.
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) will not illuminate. |
| • | No message will be displayed. |
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test. |
| • | A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. |
| • | Use a scan tool to clear DTCs. |
| • | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. |
Diagnostic Aids
| • | The modes (circuits) are displayed in order A/B/C/P. |
| • | OFF indicates the circuit low (switched / shorted to ground). |
| • | ON indicates the circuit is high (open). |
| • | If the DTC sets and the PRNDL on the IPC is flashing while driving or when the driver in not moving the gear selector lever, record the transaxle range switch input and compare the values to the chart. For example, if the driver was driving in overdrive when the PRNDL on the IPC flashed and the input read ON, OFF, ON, ON, check for an intermittent open in circuit 773. |
| • | Manipulate related wiring and connectors while observing the transaxle range switch input. If an intermittent is induced, the digit corresponding to the circuit will change. |
| • | Use the Failure Records to help determine which switch was reading incorrectly. If the DTC set and the pressure switch indicated D1and the select lever switch indicated P/N and the engine sensors (MAP, TP, MAF etc.) appear to indicate the vehicle was in Park or Neutral then check the pressure switch/circuits for an intermittent fault. |
Depending on the Scan Tool used, the transmission fluid pressure switch parameter and the gear select lever parameter may have two different titles.For example: when using a Tech 1 on a 1996 vehicle the gear select lever parameter would be named Sel. Lever Sw. and Sel. Lever Sw. A/B/C/P. The same vehicle and parameter using a Tech 2 would be named Transmission Range and T R Switch A/B/C/P. These same parameters may also call the state of the circuit differently. For example: the Tech 1 may indicate ON for an open circuit while the Tech 2 would indicate High for an open circuit. Proper verification of the parameter being observed can be indicated by the inability of the transmission fluid pressure switch to indicate any gear other than Drive 2 when the vehicle is not running (no pressure available).
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
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The adjustment procedures must be done before diagnosis of the system. This step does a comparison of both the transaxle range switch and the transaxle pressure switches. If both displays match in all gear selections then the fault is not present or may have been repaired when the adjustment procedures were performed.
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If TFP Switch doesn't match the gear selected then the transaxle pressure switches are at fault.
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Checking if the ground circuit to the switch may be at fault.
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If a circuit stays ON (High) or OFF (Low) all the time, that circuit or switch is open or shorted to ground.
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A few conditions could occur in the Transmission Fluid Pressure Manual Valve Position Switch and circuits which may not set a DTC P1810. Only one of these faults could be a circuit only or PCM fault.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | |||||||||
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Important: Perform the Park/Neutral Position Switch adjustment procedure and the Shift Cable/Lever adjustment procedure in Section 7 before proceeding with this chart.
Do the scan tool displays match each other for the range that is selected? | -- | Fault not present. Refer to Diagnostic Aids | ||||||||||
Does TFP Switch (pressure) match each range selected? | -- | |||||||||||
Do all the modes display ON (High). | -- | |||||||||||
Do any of the modes (A / B / C / P) stay ON (High) or OFF (Low) all of the time regardless of selector position? | -- | |||||||||||
6 | Do the mode(s) that did not change always display ON (High)? | -- | ||||||||||
7 |
Is the resistance on the tested CKT(s) less than the value specified? | 5 ohms | ||||||||||
8 | Repair the short to ground in the CKT(s) that have low or no resistance to ground. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
9 |
Is the resistance on the tested CKT(s) more than the value specified? | 5 ohms | ||||||||||
10 | Repair the open in the CKT(s) that have high or infinite resistance. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
11 |
Do all modes indicate ON (High)? | -- | ||||||||||
12 |
Does the display change from ON (High) to OFF (Low) when the circuit is jumpered to ground? | -- | ||||||||||
13 |
Is the resistance the same or less than the value specified? | 5 ohms | ||||||||||
14 | Repair the open/high resistance in CKT 451. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
15 |
Was a repair made? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | |||||||||
16 | Replace the transaxle range switch. Is the replacement complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
Is DTC P1810 also set? | -- | Go to DTC P1810 diagnosis | ||||||||||
18 | With the engine running, does the Trans Range (pressure) match in P, R, N, and D4 but not in D3, D2 and D1? | -- | ||||||||||
19 | Replace the Transmission Fluid Pressure Manual Valve Position Switch assembly. Is the replacement complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
20 | Disconnect the Transaxle 20 way connector and shift through gear range. Does the display ALWAYS indicate P/N? | -- | ||||||||||
21 | Check for a shorted to ground Transaxle Range B input circuit between the Transaxle 20-way connector and the PCM. Was a shorted condition repaired? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | |||||||||
22 |
Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
23 |
Was a repair made? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | |||||||||
24 | Replace the PCM. Refer to PCM Replacement/Programming . Is the replacement complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- |
