how to fix P0708 code in BMW 3 Series E90/E91 (2005-2012)

BMW 3 Series E90/E91 (2005-2012)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0708

3 min read

503 words

Problem Statement

The P0708 code indicates a malfunction related to the Transmission Range Sensor (TRS) circuit in a BMW 3 Series E90/E91 (2005-2012). This code may result in improper transmission

Error Code

P0708

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems.
•Allow the engine to cool before opening the transmission fluid access.

Symptoms

•Check engine light illuminated
•Erratic shifting or inability to shift
•Transmission stuck in a single gear
•Poor acceleration or loss of power
•Transmission fluid leaking

Diagnostic Steps

1
Scan the vehicle’s computer using an OBD-II scanner to confirm the P0708 code and check for any additional codes.
2
Inspect the Transmission Range Sensor (TRS) wiring and connectors for damage, corrosion, or loose connections.
3
Test the TRS voltage and ground signal using a multimeter to ensure it is within specifications.
4
Check transmission fluid levels and condition; low or contaminated fluid can affect transmission operation.
5
Inspect the transmission control module (TCM) for faults or programming issues.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Socket set
•Screwdriver set
•Torque wrench
•Transmission fluid (if needed)

Parts Required

•Transmission Range Sensor
•Transmission fluid (if low)

Related Faults

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Diagnostic Steps

1
Scan the vehicle’s computer using an OBD-II scanner to confirm the P0708 code and check for any additional codes.
2
Inspect the Transmission Range Sensor (TRS) wiring and connectors for damage, corrosion, or loose connections.
3
Test the TRS voltage and ground signal using a multimeter to ensure it is within specifications.
4
Check transmission fluid levels and condition; low or contaminated fluid can affect transmission operation.
5
Inspect the transmission control module (TCM) for faults or programming issues.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the negative terminal of the battery to ensure safety.
Prepare the vehicle on a level surface with parking brake engaged.

2. Inspect and Repair Wiring

Sub-steps:
- Remove the undercarriage cover if present to access the TRS wiring.
- Visually inspect the wiring harness for frays, breaks, or corrosion.
- Use a multimeter to check continuity and resistance in the wires from the TRS to the TCM.
- Repair or replace any damaged wiring or connectors.

3. Replace Transmission Range Sensor

Sub-steps:
- Locate the TRS on the transmission.
- Remove the electrical connector from the TRS.
- Unscrew the TRS from its mounting location.
- Install the new TRS by reversing the removal steps; ensure it is properly seated and secured.
- Reconnect the electrical connector.

4. Refill Transmission Fluid (if necessary)

Sub-steps:
- Check the transmission fluid level using the dipstick or fill plug.
- If low, add the manufacturer-recommended transmission fluid to the correct level.
- Ensure no leaks are present after refilling.

5. Reconnect Battery and Clear Codes

Sub-steps:
- Reconnect the negative terminal of the battery.
- Use the OBD-II scanner to clear the P0708 code.
- Start the engine and let it idle to ensure normal operation.