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P1668 Ford Code - PCM - IDM Communications Error

Quick Answer

The P1668 Ford code indicates a communication error between the Powertrain Control Module (PCM) and the Injector Driver Module (IDM) in a Ford vehicle. Common causes include Faulty wiring or connectors between the PCM and IDM, Defective PCM or IDM, Software issues within the modules. 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
P1668 Ford indicates PCM - IDM Communications Error.
Common causes
Common causes include Faulty wiring or connectors between the PCM and IDM, Defective PCM or IDM, Software issues within the modules.
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 Sep 06, 2024
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Code P1668 Ford Description

The P1668 Ford code indicates a communication error between the Powertrain Control Module (PCM) and the Injector Driver Module (IDM) in a Ford vehicle. The PCM is responsible for controlling various engine functions, while the IDM controls the fuel injectors. When these two modules are unable to communicate properly, it can lead to performance issues and potentially cause the vehicle to stall or not start at all.

OBDII Code P1668 Ford - PCM - IDM Communications Error
P1668 Ford Code - PCM - IDM Communications Error

Common Causes of P1668 Ford

  1. Faulty wiring or connectors between the PCM and IDM
  2. Defective PCM or IDM
  3. Software issues within the modules
  4. Water or moisture damage to the modules
  5. Electrical interference or grounding issues

Symptoms of P1668 Ford

  1. Engine misfires
  2. Reduced engine power
  3. Rough idling
  4. Poor fuel economy
  5. Stalling or difficulty starting the vehicle

How to Fix P1668 Ford

  1. Check and repair any faulty wiring or connectors between the PCM and IDM.
  2. Test the PCM and IDM for proper functioning and replace if necessary.
  3. Update the software in the modules to the latest version.
  4. Ensure that the modules are properly sealed to prevent water or moisture damage.
  5. Check for any electrical interference or grounding issues that may be affecting communication between the modules.

Cost to Fix P1668 Ford

The typical repair costs for addressing a PCM - IDM Communications Error in a Ford vehicle can range from $200 to $600, including parts and labor. However, the specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It is advisable to check local rates for a more precise estimate.

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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 P1668 Ford Code

1. What does the OBDII code P1668 mean on a Ford vehicle?

P1668 indicates a PCM (Powertrain Control Module) to IDM (Injector Driver Module) communication error, meaning the modules are not properly exchanging data.

2. What are the common symptoms of code P1668 on a Ford?

Symptoms may include engine misfires, rough idling, reduced power, difficulty starting, or the engine not starting at all.

3. What causes the P1668 code to appear on a Ford?

Common causes include faulty wiring or connectors between the PCM and IDM, a malfunctioning IDM, a defective PCM, or issues with the power or ground circuits.

4. Can a blown fuse cause the P1668 code on a Ford?

Yes, a blown fuse in the IDM circuit can disrupt communication between the PCM and IDM, triggering the P1668 code.

5. How do I diagnose the P1668 code on my Ford vehicle?

Start by checking the wiring and connectors between the PCM and IDM for damage or loose connections. Verify power and ground to both modules, and test the IDM and PCM for proper functionality.

6. Can I drive my Ford with the P1668 code active?

Driving with the P1668 code is not recommended, as it can lead to poor performance, engine damage, or a complete engine failure.

7. How do I fix the P1668 code on a Ford?

Repairs may include fixing damaged wiring or connectors, replacing a faulty IDM or PCM, or addressing issues in the power or ground circuits.

8. Can a software update resolve the P1668 code on a Ford?

In rare cases, reprogramming or updating the PCM software may resolve the communication error if it is caused by a software glitch.

9. How much does it cost to repair the P1668 code on a Ford?

The cost varies depending on the underlying issue, ranging from $50–$150 for minor wiring repairs to $500 or more for module replacement and reprogramming.

10. Do I need to replace both the PCM and IDM for the P1668 code?

Not necessarily. Only replace the PCM or IDM after confirming that one of them is faulty through proper diagnostics.

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