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P1605 Mercury Code - PCM Keep Alive Memory Test Error Conditions

Quick Answer

The P1605 diagnostic trouble code for Mercury vehicles indicates a PCM (Powertrain Control Module) Keep Alive Memory Test Error Conditions. Common causes include Weak or dead battery, Faulty PCM, Corroded or loose electrical connections. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1605 Mercury indicates PCM Keep Alive Memory Test Error Conditions.
Common causes
Common causes include Weak or dead battery, Faulty PCM, Corroded or loose electrical connections.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Aug 25, 2024
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Code P1605 Mercury Description

The P1605 diagnostic trouble code for Mercury vehicles indicates a PCM (Powertrain Control Module) Keep Alive Memory Test Error Conditions. The PCM is a crucial component of the vehicle's engine management system, responsible for controlling various functions such as fuel injection, ignition timing, and emissions control. The Keep Alive Memory (KAM) is a section of the PCM that retains important data even when the vehicle is turned off, such as learned adaptations and sensor calibration values.

OBDII Code P1605 Mercury - PCM Keep Alive Memory Test Error Conditions
P1605 Mercury Code - PCM Keep Alive Memory Test Error Conditions

Common Causes of P1605 Mercury

  1. Weak or dead battery
  2. Faulty PCM
  3. Corroded or loose electrical connections
  4. Wiring issues
  5. Software glitches or malfunctions

Symptoms of P1605 Mercury

  1. Rough idling
  2. Poor fuel efficiency
  3. Hesitation or stalling during acceleration
  4. Difficulty starting the vehicle
  5. Illumination of the check engine light

How to Fix P1605 Mercury

  1. Check and replace the vehicle's battery if necessary.
  2. Inspect and clean electrical connections to ensure a good connection.
  3. Scan the PCM for error codes and address any other related issues.
  4. Reset the Keep Alive Memory by disconnecting the battery and waiting for at least 30 minutes.
  5. If the issue persists, consider replacing the PCM or seeking professional diagnostic assistance.

Cost to Fix P1605 Mercury

The cost of repairing a PCM Keep Alive Memory Test Error Conditions can vary depending on the specific cause of the issue and the labor rates of the repair shop. Generally, the repair cost can range from $200 to $500, including parts and labor. It is important to note that diagnostic time and labor rates can vary, so it is advisable to get a few quotes from different auto repair shops to determine the most cost-effective option.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1605 Mercury Code

1. What does the OBDII code P1605 mean for a Mercury vehicle?

P1605 indicates a "PCM Keep Alive Memory Test Error," meaning the Powertrain Control Module (PCM) has detected an issue with retaining memory when the vehicle is off.

2. What are the common symptoms of code P1605 in a Mercury?

Symptoms can include a check engine light, poor engine performance, difficulty starting, or loss of previously stored adaptive data like fuel trims.

3. What causes the P1605 code to be triggered?

Common causes include a weak or disconnected battery, faulty PCM, damaged wiring, or issues with the keep-alive memory (KAM) circuit.

4. Can a low battery cause the P1605 code on a Mercury?

Yes, a low or failing battery can cause the PCM to lose its memory, triggering the P1605 code.

5. How do I fix the P1605 code on my Mercury?

Start by checking the battery and charging system. Repair or replace any damaged wiring or connections. If the issue persists, the PCM may need reprogramming or replacement.

6. Can I drive my Mercury with the P1605 code?

While the vehicle may still be drivable, you could experience performance issues, and prolonged driving with this code may lead to further complications.

7. How do I reset the PCM Keep Alive Memory on a Mercury?

Disconnect the negative battery terminal for about 15 minutes, then reconnect it. This will clear stored data, but it won't address the underlying issue causing the P1605 code.

8. Does the P1605 code always mean the PCM is faulty?

No, a faulty PCM is just one possible cause. Always check the battery, wiring, and connections before replacing the PCM.

9. How much does it cost to repair a P1605 code on a Mercury?

Costs vary depending on the cause, but battery replacement typically costs $100-$200, while PCM replacement and programming can range from $500-$1,500.

10. Can an aftermarket battery trigger the P1605 code?

Yes, if the battery's voltage is inconsistent or if installation caused poor connections, it can lead to memory retention issues and trigger the code.

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