P0706
DTC P0706
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0706
- Transmission Range Sensor Circuit Performance
Typical Scan Tool Data
Circuit/System Description
The internal mode switch (IMS) consists of 5 internal switches, A, B, C, P and Neutral Start (NS). The IMS is attached to the selector shaft, and the switches change state depending on the position of the selector shaft. The TCM uses four of the internal switches, A, B, C, and P, to determine the gear range that is selected. The ECM uses the NS switch as confirmation that the transmission is in neutral or park before the engine starter is engaged.
Conditions for Running the DTC
* DTC P0706 is not set.
* Ignition voltage is between 9-18 V.
* Engine speed is greater than 100 RPM and less than 350 RPM.
* Engine cranking.
Conditions for Setting the DTC
The TCM detects engine cranking when the IMS does note indicate park or neutral for 0.2 seconds.
Action Taken When the DTC Sets
* DTC P0706 is a Type B DTC.
* The TCM inhibits range and commands neutral. Driver is required to select neutral and then select drive or reverse to attain a range.
Conditions for Clearing the DTC
DTC P0706 is a Type B DTC.
Diagnostic Aids
* Engine cranking is required to experience a condition.
* An intermittent open or short to ground may cause this DTC.
* If DTC P0708 was in TCM history, perform diagnostic for DTC P0708 first.
Circuit/System Verification
1. Verify the range selector lever cable adjustment is correct; refer to Range Selector Lever Cable Adjustment (Allison - Automatic Transmission).
2. Ignition ON, engine OFF, move the shift selector lever through all the ranges. With a scan tool, verify the Tr SW A/B/C/P parameters match the IMS A, B, C, and P states in the transmission IMS logic table. Refer to Transmission Internal Mode Switch Logic (Transmission Internal Mode Switch Logic).
• If not the expected results, refer to DTC P0708 (P0708).
3. Verify that the engine will not crank in range selector positions other than PARK and NEUTRAL positions.
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the X175 harness connector at the transmission.
2. Start the engine. The engine should not crank over.
• If the engine cranks over, refer to Starter Solenoid Does Not Click (Starter Solenoid Does Not Click).
3. Ignition OFF, install the X175 harness connector at the transmission.
4. Remove the transmission oil pan and internal filter. Refer to Oil Pan Replacement (Allison - Automatic Transmission).
5. Disconnect the IMS connector.
6. Start the engine. The engine should not crank over.
• If the engine cranks over, replace the transmission internal wire harness assembly. Refer to Wiring Harness Replacement (Allison - Automatic Transmission).
7. If all the circuits test normal, replace the IMS. Refer to Transmission Internal Mode Switch Replacement (Service and Repair).
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Transmission Internal Mode Switch Replacement (Service and Repair)
* Wiring Harness Replacement (Allison - Automatic Transmission)
Repair Verification
If another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) and perform the appropriate diagnostic procedure.