Error Code P0660 is defined as Intake Manifold Tuning Valve Control Circuit/Open Bank 1. This means there’s a problem with the bank 1 of the engine intake manifold turning valve control circuit, which is usually caused by damaged wires or defective PCM.

This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, particularly vehicles made since 1996 up to present. Specifications on the definition, troubleshooting and repairs of course, vary from one vehicle make and/or model to another.


As said earlier, this code indicates an error detected by the PCM in the intake manifold control circuit for engine bank 1. It can also be detected by one of the engine’s supporting control module, including but not limited to, body control module, transmission control module, antilock brake control module, turbo control module, instrument panel control module, anti-theft module, traction control module, cruise control module, climate control module, and proximity alert module.

When an intake manifold turning valve control circuit experiences an error, it will store a trouble code and activate the Check Engine light. For some vehicle models, they require multiple drive cycles (up to 8) with a failure to activate the Check Engine light, while other activate the light right from the initial failure.

Common Symptoms

Like other error codes, Error Code P0660 will trigger the Check Engine light. But if it doesn’t, then the code may be pending or stored. Other symptoms include:

  • Poor engine performance
  • Weak acceleration
  • Rough idling
  • Engine stalls
  • Poor fuel economy

Possible Causes

Though many times there is hardly even a problem with the PCM itself, Error Code P0660 is the exception to this rule. And with this, it can be caused by multiple factors, such as:

  • corroded, open or shorted connectors that damaged connectors or wirings in the CAN bus harness
  • Loose control module
  • Broken ground wire
  • Defective fuel injector control module
  • Defective CAN bus

How to Check

Error Code P0660 is usually related with the controller area network bus (CAN), which is what connects the communication between the vehicle and multiple microcontrollers to regular electrical functions. The PCM works as the master controller, and from time to time, individual controllers may fail. Thus, technicians will have to check each module involved and replace any ones that are defective. The process includes:

  • Checking wiring and connectors and replacing any damaged components
  • Retesting the system
  • Record the freeze frame data and codes, and then clear them out to see if they reappear
  • For intermittent codes, the problem may be allowed to worsen for a proper diagnosis and repair approach
  • Technicians will have to use special scanners such as Authohex or Tech II to find the general area where the issue is happening
  • Disconnect and test each CAN bus pin (this step could be time-consuming, and must be avoided as much as possible)
  • Using the battery ground, the technicians will check the control module ground circuits
  • Then, they find ground discrepancies using auxiliary ground cable
  • Next, they look for loose or corroded connectors that could lead to increased circuit resistance
  • They also check each controller connector for continuity using DVOM (digital volt-ohmmeter) and CAN bus wiring diagram, possible with a pin out value chart
  • Then, they compare the results with the specifications provided by the vehicle’s manufacturer and fix open or shorted circuits
  • If the problem still exists, then that means replacing the PCM

How to Fix

Error Code P0660 is pretty easy to repair. First off, bad wirings, connectors and modules must be repaired or replaced.

If needed, the CAN bus must be replaced.

In some cases, the PCM itself must be replaced

This error code is often misdiagnosed in response to engine misfire, lean exhaust or fuel injector issue, and replacing the wrong components of course, will never fix the problem. That is why it is crucial to have a proper diagnosis.

Due to wiring harness’ complexity, many people find it more economical to replace them rather than spend time repairing the wiring.