The transmission range (TR) switch is part of the park/neutral position and back-up lamp switch assembly and is mounted on the transmission manual shaft. The TR switch is a multi-signal switch. The PCM supplies ignition voltage to the TR switch on four signal circuits, A, B, C, and P. Each gear selector lever position grounds one or more of the signal circuits in a unique pattern. In order to determine the gear range selected by the driver, the PCM compares the voltage combination on the signal circuits to a TR switch combination table stored in memory.
Refer to Transmission Range Switch Logic for valid combinations of switch signal circuits A, B, C and P.
The numbers below refer to the step numbers on the diagnostic table.
By disconnecting the TR switch, the ground path for all TR switch circuits would be removed and the PCM should recognize all circuits as open. The scan tool should display HI for all range signals.
This step tests the TR switch wiring for an open or lack of signal voltage from the PCM.
This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal A should change to LOW.
This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal B should change to LOW.
This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal C should change to LOW.
Step | Action | Value(s) | Yes | No | ||||||||||||||
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1 |
Does each selected transmission range match the scan tool TR Sw. display? | -- | Go to Intermittent Conditions in Engine Controls - 3.1L | Go to Step 2 | ||||||||||||||
2 |
Did you find and correct a condition? | -- | Go to Step 15 | Go to Step 3 | ||||||||||||||
3 | With the scan tool, observe the TR Sw. A/B/C/P display. Does the scan tool TR Sw. A/B/C/P parameter indicate HI for all range signal states? | -- | Go to Step 12 | Go to Step 4 | ||||||||||||||
Does the scan tool TR Sw. A/B/C/P parameter indicate HI for all range signal states? | -- | Go to Step 5 | Go to Step 9 | |||||||||||||||
Does the voltage measure within the specified value at all four terminals? | 10-12 V | Go to Step 6 | Go to Step 10 | |||||||||||||||
Connect a fused jumper wire from terminal D of the TR switch 4-way connector, signal A circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal A circuit (CKT 771) is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 11 | Go to Step 7 | |||||||||||||||
Connect a fused jumper wire from terminal B of the TR switch 4-way connector, signal B circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal B circuit (CKT 772) is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 11 | Go to Step 8 | |||||||||||||||
Connect a fused jumper wire from terminal C of the TR switch 4-way connector, signal C circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal C circuit (CKT 773) is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 11 | Go to Step 13 | |||||||||||||||
9 | Test the signal circuits (CKTs 771, 772, 773 and 776) of the TR switch that did not indicate HI for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||||||||||
10 | Test the signal circuits (CKTs 771, 772, 773 and 776) of the TR switch that did not indicate proper voltage for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||||||||||
11 | Test the affected signal circuits of the TR switch for a shorted together condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||||||||||
12 | Test the ground circuit (CKT 451) of the TR switch for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 | ||||||||||||||
13 | Replace the TR switch. The TR switch is part of the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||||||
14 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 3.1L. Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||||||
15 |
Does each selected transmission range match the scan tool TR Sw. display? | -- | System OK | Go to Step 2 |