1, 2 and 3 Digit Codes: 28

CODE NUMBER
Scan tool: 28
General scan tool: P0705

CODE NAME
Check shifter signal

CODE DESCRIPTION
Technical Description
Transaxle range sensor 1, 2, 41, 43 (TCM terminals 1, 2, 41, and 43) circuits communicate the shift lever position to the TCM. Each circuit is terminated at the transmission with a switch. Each switch can be either open or closed, depending on the shift lever position. The TCM can decode this information and determine the shift lever position. Each shift lever position has a certain combination of switches which will be open and closed, this is called a PRNDL code. Since there are 4 switches, there are 16 possible combinations of open and closed switches (codes). Most vehicles have only 7 gear positions and there are three recognized between gear codes, this results in 6 codes which should never occur, these are called invalid codes.

Check Area
Continuously with the key on.

Set Conditions
3 occurrences in one key start of an invalid PRNDL code which lasts for more than 0.1 second.

PROBABLE CAUSE
- Wrong part number TCM for application
- Transaxle range sensor 1, 2. 41, 43 (TCM terminals 1, 2, 41, and 43) circuits are either open, shorted to ground, or shorted to 12 volts.
- Transaxle range sensor connector not plugged in.
- Worn Manual Level (Rooster Comb). Check for heavy wearing by transaxle range sensor or switch contacts.
- Intermittent transaxle range sensor 1, 2, 41, 43 (TCM terminals 1, 2, 41, and 43) circuits. Check for corrosion, terminal push-outs or spread terminals at TCM 60-way connector and/or transaxle range sensor 1O-way connector.
- Defective transaxle range sensor
- Defective TCM.





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