🚨 Diagnostic Profile
Vehicle Make: Chrysler
Description: Cruise Control System Transaxle Not In Drive. The cruise control system is inhibited because the transmission range input does not report Drive to the controlling module.
🚨 Repair Difficulty Tier
Tier: [Intermediate]
Diagnosis requires electrical testing of the transmission range input and cruise control circuits. Component replacement is typically straightforward once the faulty part is confirmed.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Verify the transmission shift lever position and confirm the gear selector indicator matches the selected range.
- Inspect the Transmission Range (TR) sensor connector, typically mounted on the valve body or shift shaft at the transaxle case, for corrosion, spread pins, loose fit, or moisture intrusion.
- Check the TR sensor mounting and manual lever linkage adjustment for looseness, worn detents, or misalignment that could cause an incorrect gear range signal.
- Review stored diagnostic trouble codes and freeze frame data related to the transmission range input (commonly P0706, P0708, or related PRNDL circuit codes) and cruise control inhibit codes.
- Check battery state of charge and charging system output using a digital multimeter, since low system voltage can cause erratic range sensor readings or false PCM/TCM inputs.
- Inspect wiring harness routing near the transaxle case and bellhousing area for chafing, pinching, or heat damage, paying close attention to areas near the exhaust crossover and engine mounts where harness rub-through commonly occurs.
Step 2: Diagnostic Verification
- Connect a scan tool capable of bi-directional controls and monitor the Transmission Range Switch/PRNDL state parameter while slowly moving the shift lever through each detent position.
- Confirm the range input reads Drive only in the correct position and does not toggle, drop out, or lag during shifts or while driving over rough roads.
- Using a digital multimeter, verify reference voltage (typically 5V supplied by the PCM/TCM) is present at the sensor power circuit with the key on, engine off, backprobing the connector to avoid terminal damage.
- Verify the signal return voltage changes in a stepped or digital pattern as the lever is moved through each gear range, confirming a clean, distinct voltage for Park, Reverse, Neutral, and Drive with no intermediate or erratic readings.
- Check the sensor ground circuit for continuity and resistance; a good chassis or sensor ground should read close to 0 ohms. Any measurable resistance above a few ohms indicates a corroded or damaged ground path.
- Test the cruise control multifunction switch, brake pedal position switch, and brake light circuit for proper operation, since both the TR sensor state and brake switch status must be valid for the PCM/TCM to enable cruise control engagement.
- Perform a full continuity and resistance check of the wiring harness between the TR sensor connector and the PCM/TCM connector pins using the OEM wiring diagram specific to this model year and powertrain combination, checking for opens, shorts to ground, or shorts to power.
Step 3: Resolution & Reset Process
- Repair any harness damage, corroded terminals, or loose connections found during inspection using OEM-spec connectors, weatherproof splices, and dielectric grease.
- If the TR sensor is faulty, out of calibration, or fails bench/voltage specification testing, replace it and perform the manual lever and sensor alignment procedure per OEM service specification to properly index Park, Reverse, Neutral, and Drive positions.
- Clear all stored diagnostic trouble codes with the scan tool and verify no codes return immediately with the key on, engine running.
- Perform a complete key cycle (off for at least 30 seconds) and a road test through a full range of shifting conditions and speeds to confirm the TR sensor reports Drive accurately and that the cruise control system engages and holds set speed without inhibit faults.
- Recheck for stored or pending codes after the road test using the scan tool, and document the final sensor voltage readings and any TCM/PCM adaptive relearn status for the service record.
📦 Parts, Labor, and Budget Estimates
Required Components/Software:
- Transmission Range (TR) sensor/Neutral Safety Switch assembly, OEM or OEM-equivalent, specific to transaxle model
- Connector pigtail repair kit with OEM-style terminals, heat-shrink splices, and dielectric grease
- Replacement wiring harness section or transmission case connector pigtail, if damage is confirmed
- OEM-level scan tool (such as a Chrysler-compatible diagnostic platform) with current module software calibration for PCM/TCM communication and any required TR sensor relearn procedure
Average Component Price:
- TR sensor/Neutral Safety Switch: approximately $60–$220 depending on transaxle application (part only)
- Connector and wiring repair materials: approximately $15–$60
- Diagnostic scan and software access fees: approximately $100–$180 (independent shop) or $150–$250 (dealer diagnostic flat rate)
Estimated Labor Hours:
- Diagnosis and electrical verification (scan tool monitoring, voltage/resistance testing, wiring diagram tracing): 1.0–1.5 hours
- TR sensor replacement and manual lever alignment/adjustment: 0.8–1.5 hours (additional time if linkage or internal transaxle access is required on certain transaxle models)
- Final verification, code clearing, and road test: 0.3–0.5 hours
- Total estimated shop time: approximately 2.1–3.5 hours, with total estimated repair cost (parts and labor combined) typically ranging from $250 to $600 depending on labor rate and vehicle-specific access difficulty