Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Aids
DTC 28 will set if PCM detects one of 2 illegal combinations. See TRANS. RANGE PRESSURE SWITCH COMBINATIONS table. Check all wiring connectors for proper terminal tension. For current DTC 28, range signal will default to D4 while A/B/C range values continue to read actual trans. range pressure switch output for each range selection.
| Application | A | B | C | ||||
|---|---|---|---|---|---|---|---|
| Park | Off | On | Off | ||||
| Reverse | On | On | Off | ||||
| Neutral | Off | On | Off | ||||
| 4th | Off | On | On | ||||
| 3rd | Off | Off | On | ||||
| 2nd | Off | Off | Off | ||||
| 1st | On | Off | Off | ||||
| Illegal | On | Off | On | ||||
| Illegal | On | On | On | ||||
|
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| Application | A | B | C | ||||
|---|---|---|---|---|---|---|---|
| Park | On | Off | On | ||||
| Reverse | Off | Off | On | ||||
| Neutral | On | Off | On | ||||
| 4th | On | Off | Off | ||||
| 3rd | On | On | Off | ||||
| 2nd | On | On | On | ||||
| 1st | Off | On | On | ||||
| Illegal | Off | On | Off | ||||
| Illegal | Off | Off | Off | ||||
|
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NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.