The TCM also communicates the park/neutral switch status to the BCM via serial data. The BCM uses this data to control the Electronic PRNDL display on the shifter. The BCM controls the LED's in the PRNDL display through 4 control circuits. The BCM has 8 DTCs for these 4 control circuits. These DTCs diagnose a shorted or an open for each circuit.
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 voltage path for all TR switch circuits would be removed and the TCM should recognize all circuits as open. The scan tool should display HIGH for all range signals.
This step tests the TR switch wiring for an open or short to ground from the TCM.
This step tests the TR switch wiring and the TCM by providing a voltage path through a fused jumper wire. When jumpered, the scan tool range signal A should change to LOW.
This step tests the TR switch wiring and the TCM by providing a voltage path through a fused jumper wire. When jumpered, the scan tool range signal B should change to LOW.
This step tests the TR switch wiring and the TCM by providing a voltage path through a fused jumper wire. When jumpered, the scan tool range signal C should change to LOW.
Step | Action | Values | Yes | No | ||||||||||||||||
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1 |
Does each selected transmission range match the scan tool TR Sw. display? | -- | Go to Testing for Intermittent Conditions and Poor Connections | 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 LOW 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 HIGH for all range signal states? | -- | Go to Step 5 | Go to Step 9 | |||||||||||||||||
Does the voltage measure within the specified range at all four terminals? | 10-12 V | Go to Step 6 | Go to Step 10 | |||||||||||||||||
Connect a fused jumper wire from terminal 10 of the TR switch 10-way connector, signal A circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal A circuit is jumpered, do any other signal circuits indicate LOW? | -- | Go to Step 11 | Go to Step 7 | |||||||||||||||||
Connect a fused jumper wire from terminal 6 of the TR switch 10-way connector, signal B circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal B circuit is jumpered, do any other signal circuits indicate LOW? | -- | Go to Step 11 | Go to Step 8 | |||||||||||||||||
Connect a fused jumper wire from terminal 5 of the TR switch 10-way connector, signal C circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal C circuit is jumpered, do any other signal circuits indicate LOW? | -- | Go to Step 11 | Go to Step 13 | |||||||||||||||||
9 | Test the signal circuit or circuits of the TR switch that did not indicate HIGH for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||||||||||||
10 | Test the signal circuit or circuits of the TR switch that did not indicate proper voltage for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . 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 . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||||||||||||
12 | Test the voltage supply circuit of the TR switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 | ||||||||||||||||
13 | Replace the TR switch. Refer to Transmission Range Switch Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||||||||
14 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. 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 |