P0887 — TCM Power Relay Control Circuit High #

Note: The code description may vary depending on the vehicle manufacturer (OEM). Always refer to your service manual for the exact definition used by your brand.

• P0887 – Transmission Control Module Power Relay Sense Circuit High (Chrysler/Dodge/Jeep/RAM)
• P0887 – TCM Power Relay Control Circuit High (General Use)
• P0887 – Transmission Control Relay High (Honda/Acura)
• P0887 – Transmission Control Module Power Relay Sense Circuit High Voltage (Ford)

Summary of the P0887 Code #

P0887 is a diagnostic trouble code (DTC) that indicates an issue with the Transmission Control Module (TCM) Power Relay Control Circuit. The TCM is responsible for managing the operation of the automatic transmission by sending signals to solenoids and sensors. When this code sets, it means the vehicle’s powertrain control module (PCM) or TCM has detected an abnormally high voltage in the relay control circuit that supplies power to the TCM. This could be the result of a short, an open circuit, excessive resistance, or even a faulty relay. The outcome is often an automatic transmission that may not shift as expected, and the vehicle may enter a “limp” mode to prevent further damage. Addressing this code promptly is crucial to avoid costly transmission repairs and restore normal drivability.

Common Symptoms for Code P0887 #

When the P0887 code is present, your vehicle may display several noticeable symptoms related to transmission operation and overall drivability. In many cases, the Check Engine Light will be illuminated. Some symptoms may be subtle at first, but tend to worsen if ignored. Look out for the following:

• Check Engine Light or Transmission Warning Light illuminated
• Transmission stuck in limp mode (limited gears, reduced performance)
• Harsh or delayed shifting
• No shift — the transmission may not shift at all
• Failure to engage into drive or reverse
• Reduced fuel economy
• Possible blown fuses related to transmission circuits

Probable Causes for Code P0887 #

Several underlying factors can trigger the P0887 code. Understanding the most frequent causes can help you pinpoint the issue more efficiently. Typically, these are related to electrical faults, but sometimes, mechanical issues or even control module failure can be at play.

1. Faulty transmission control relay (stuck closed, causing high circuit voltage)
2. Short to voltage or open circuit in the relay control wiring harness
3. Damaged or corroded wiring/connectors to the TCM or relay
4. Faulty Transmission Control Module (TCM)
5. Issues with the Powertrain Control Module (PCM) (rare, but possible)
6. Blown or incorrectly rated fuse in the relay supply circuit

Step-by-Step Diagnostic Process for P0887 #

Diagnosing a P0887 code requires a methodical approach, combining visual inspection, electronic testing, and sometimes component substitution. Do not rush—systematically move from the easiest checks to the most complex. Here’s how a professional technician would approach it:

• Step 1: Use a scan tool to confirm the presence of P0887 and check for any related DTCs (especially those concerning transmission or electrical issues).
• Step 2: Clear the code and see if it returns immediately. If so, the issue is usually a hard fault (not intermittent).
• Step 3: Visually inspect the TCM power relay, connectors, and wiring for damage, corrosion, or loose connections—especially near the battery and underhood fuse box.
• Step 4: Test the TCM power relay using a multimeter. Check for proper relay operation (verify coil resistance and switching function).
• Step 5: Inspect the relay control circuit for continuity, shorts to voltage, or excessive resistance. Wiggle test the harness to spot intermittent faults.
• Step 6: Check all related fuses and ensure they are the correct type and rating (refer to your OEM’s service manual).
• Step 7: If all wiring and relay tests pass, consider testing the TCM and PCM for internal faults. Substitute with a known-good unit only as a last resort.

Possible Repairs for Code P0887 #

Once the root cause is identified, the appropriate repair can be performed. Many fixes are straightforward and cost-effective, but some may require professional attention, especially if module replacement or reprogramming is necessary.

• Replace a faulty TCM power relay (the most common fix)
• Repair or replace damaged wiring or corroded connectors in the relay control circuit
• Replace blown or incorrect fuses associated with the transmission relay or TCM power supply
• Clean terminals and apply dielectric grease to prevent future corrosion
• Replace the Transmission Control Module (TCM) if verified to be faulty (may require programming)
• Address PCM issues if diagnostics point to a control module fault (rare; consult OEM procedures)

Is It Safe to Drive with Code P0887? #

No, it is not recommended to drive with code P0887 active. The code indicates a critical problem with the power supply to the transmission control system. This can result in unpredictable shifting, loss of certain gears, or even the inability to move the vehicle. In many cases, the car will enter limp mode, restricting speed and power. Continuing to drive may cause further damage to the transmission or related components. If P0887 appears, address it as soon as possible to protect your vehicle and ensure your safety.

Vehicles Most Commonly Affected by Code P0887 #

While P0887 is a generic OBD-II code, it is more frequently reported on vehicles from certain manufacturers, especially those with known relay or wiring vulnerabilities. If you drive one of these, be extra vigilant:

• Dodge, Chrysler, Jeep, and RAM vehicles (automatic transmissions, especially mid-2000s to mid-2010s)
• Ford (select models with electronic transmissions)
• Honda and Acura (mainly 2000s models)
• General Motors (Chevrolet, GMC, Buick with 6-speed/8-speed automatics)
• Nissan and Infiniti (CVTs and automatic transmissions)

Common Mistakes and Best Practices for Code P0887 #

Misdiagnosing P0887 can lead to unnecessary parts replacement and wasted time. To avoid common pitfalls, follow these proven best practices:

• Do not replace the TCM or PCM before thoroughly checking the relay, wiring, and connectors.
• Always inspect and test fuses, even if they look visually intact—use a multimeter for confirmation.
• Check for corrosion or water intrusion in underhood fuse boxes, a common source of relay circuit issues.
• Use the correct relay part number specified by the OEM; aftermarket relays may not meet exact requirements.
• Document any intermittent issues or “limp mode” incidents—they can help pinpoint wiring problems.

Express FAQ for P0887 #

Here are quick answers to common questions about the P0887 code:

• Q: Will clearing the code fix the problem?
  A: No. Clearing the code without addressing the underlying electrical fault will only result in the code returning. Proper diagnosis and repair are necessary.
• Q: Do I need to reprogram the TCM after repair?
  A: In most cases, no reprogramming is needed if you replaced only the relay or repaired wiring. However, if the TCM itself is replaced, reprogramming to match your vehicle’s VIN and configuration may be required—consult your OEM service manual for instructions.