The P0987 trouble code is an OBD-II diagnostic code that indicates a problem with the transmission fluid pressure sensor or switch “E” circuit. This code is crucial for maintaining optimal transmission performance, as it signals that the Engine Control Module (ECM) has detected an abnormal voltage reading from the transmission fluid pressure sensor. If not addressed, this issue can lead to significant transmission problems, including erratic shifting and potential damage to the transmission system.
| P0987 Code Meaning | P0987 Code Common Causes |
|---|---|
| Transmission Fluid Pressure Sensor/Switch “E” Circuit Malfunction | Faulty transmission fluid pressure sensor |
| Out-of-Range Voltage Reading from Sensor | Wiring issues (shorts, opens, or corrosion) |
| Malfunction in Transmission Control Module (TCM) | Low transmission fluid level |
| Internal Transmission Problems | Contaminated transmission fluid |
| Electrical Connection Issues | Faulty transmission solenoid |
Symptoms of P0987 Code
When the P0987 code is triggered, vehicle owners may notice various symptoms that indicate a problem with the transmission system. Common symptoms include:
- Malfunction Indicator Light (MIL): The check engine light illuminates on the dashboard.
- Erratic Shifting: The vehicle may experience harsh or delayed shifts between gears.
- Limp Mode Activation: The vehicle may enter limp mode, starting off in second or third gear to prevent further damage.
- Poor Acceleration: The vehicle may struggle to accelerate smoothly.
Understanding these symptoms is essential for diagnosing the underlying issue effectively.
Technical Explanation of P0987 Code
The P0987 code specifically relates to the Transmission Fluid Pressure Sensor/Switch “E” circuit. This sensor plays a critical role in monitoring the hydraulic pressure within the transmission, which is vital for proper shifting and overall performance. When the ECM detects that the voltage signal from this sensor is outside of the expected range, it triggers the P0987 code.
How the Transmission Fluid Pressure Sensor Works
The transmission fluid pressure sensor measures the hydraulic pressure in the transmission system and sends this information to the TCM or ECM. These modules use this data to control shift timing and ensure smooth operation. If there is a fault in this circuit—whether due to a malfunctioning sensor, wiring issues, or internal transmission problems—the ECM will set the P0987 code.
Step-by-Step Diagnosis of P0987 Code
Diagnosing a P0987 trouble code involves a systematic approach that includes visual inspections and electrical testing. Here’s how to proceed:
Step 1: Gather Tools and Equipment
Before starting your diagnosis, ensure you have the following tools:
- OBD-II scanner
- Digital multimeter (DMM)
- Basic hand tools (screwdrivers, wrenches)
- Electrical contact cleaner
- Safety gloves and goggles
Step 2: Scan for Codes
Use an OBD-II scanner to check for any stored trouble codes. Take note of any additional codes that may be present alongside P0987, as these can provide valuable insights into related issues.
Step 3: Inspect Transmission Fluid Level and Condition
Check the transmission fluid level using the dipstick. If it’s low, top it up with the manufacturer-recommended fluid. Additionally, inspect the fluid quality; if it’s dark or has a burnt smell, it may need to be replaced.
Step 4: Visual Inspection of Wiring and Connectors
Locate the Transmission Fluid Pressure Sensor/Switch “E.” This sensor is typically located on or near the valve body of the transmission. Inspect all wiring and connectors for signs of damage such as fraying, corrosion, or loose connections.
Step 5: Test Voltage at Sensor
With your DMM:
- Disconnect the sensor connector.
- Set your DMM to measure DC voltage.
- Turn on the ignition (engine off) and measure voltage at the connector terminals.
- Compare your readings with manufacturer specifications; typically, you should see around 5V or 12V.
If voltage readings are incorrect, trace back through wiring for shorts or opens.
Step 6: Test Resistance of Sensor
Next, measure resistance across the sensor terminals:
- With the connector still disconnected, set your DMM to measure resistance (ohms).
- Compare your readings against manufacturer specifications.
If resistance values are out of range, replace the sensor.
Step 7: Check TCM Functionality
If all previous tests pass but you still have a P0987 code, consider testing or replacing the TCM. Ensure that any replacement module is properly programmed for your vehicle.
Solution Methods for P0987 Code
Once you’ve diagnosed the issue causing the P0987 code, you can implement solutions based on your findings:
Repairing Wiring Issues
If you find damaged wiring or connectors during your inspection:
- Repair any frayed wires using solder and heat shrink tubing.
- Replace corroded connectors with new ones to ensure good electrical contact.
Replacing Faulty Components
If tests indicate a faulty Transmission Fluid Pressure Sensor/Switch:
- Disconnect and remove the old sensor.
- Install a new sensor following manufacturer guidelines.
- Reconnect all wiring securely.
Flushing Transmission Fluid
If contaminated fluid was found during inspection:
- Flush out old fluid using a professional service or DIY method.
- Replace with fresh transmission fluid according to specifications.
Professional Help
If internal mechanical issues are suspected within the transmission:
- Consult a professional mechanic for further diagnosis and potential rebuilding of internal components.
Cost Estimates for Repairs
The cost of repairs related to a P0987 code can vary widely depending on several factors:
- Transmission Fluid Change: $100 – $200
- Transmission Fluid Pressure Sensor Replacement: $150 – $300
- Wiring Repairs: $50 – $150
- Transmission Control Module Replacement: $500 – $1,500 (including programming)
It’s advisable to get multiple quotes from different repair shops to ensure fair pricing.
Warnings and Recommendations
Important: Always follow safety precautions when working on your vehicle. If you are unsure about any step in diagnosing or repairing issues related to P0987, seek assistance from a qualified automotive technician.
Closing Paragraph
The P0987 trouble code signifies an important issue within your vehicle’s transmission system that should not be ignored. By understanding its implications and following systematic diagnostic steps, vehicle owners can effectively address this problem before it leads to more serious complications. Whether you’re a seasoned DIY mechanic or a novice car owner, being informed about this code will help you maintain your vehicle’s performance and longevity.
Frequently Asked Questions About P0987
- What does error code P0987 mean?
P0987 indicates a malfunction in the Transmission Fluid Pressure Sensor/Switch “E” circuit. - What are common symptoms of P0987?
Common symptoms include erratic shifting, limp mode activation, and illumination of the check engine light. - Can I drive my car with a P0987 code?
While it may be possible to drive short distances, it’s not recommended as it can lead to further transmission damage. - How do I fix error code P0987?
Fixing this error typically involves checking fluid levels, inspecting wiring and connectors, replacing faulty sensors, or addressing TCM issues. - Is it safe to replace a Transmission Fluid Pressure Sensor myself?
If you have basic mechanical skills and tools, it’s generally safe; however, consult your vehicle’s manual for specific instructions. - What if I clear the code but it comes back?
If clearing does not resolve it permanently, further diagnosis is needed as there may be underlying issues. - How much does it cost to repair P0987?
The costs can range from $100 for fluid changes up to $1,500 for TCM replacements. - Should I consult a professional mechanic?
If you’re unsure about diagnosing or repairing yourself, it’s best to consult a professional mechanic.