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P0649 is a diagnostic trouble code (DTC) for "Speed Control Lamp Control Circuit". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
A P0649 trouble code indicates that the Powertrain Control Module (PCM) or one of the other control modules has detected a problem with the speed control lamp circuit. In addition to the PCM, other control modules that might detect this fault include the alternative fuel control module, anti-theft control module, anti-lock brake control module, body control module, climate control module, cruise control module, fuel injection control module, instrument panel control module, proximity alert module, traction control module, and turbo control module. Some related codes include the P0648 and P0650 trouble codes.
When a problem with the speed control lamp circuit is detected, a code is stored on the PCM and the Check Engine Light illuminates. Some vehicle models require multiple drive cycles, up to eight, with a failure before the Check Engine Light illuminates.
Some common causes of a P0649 trouble code include:
In addition to a stored P0649 trouble code, symptoms of this code include an illuminated or flashing speed control lamp, a speed control lamp that fails to light, and an illuminated Check Engine Light.
To diagnose a P0649 trouble code, a mechanic needs an OBD-II scanner or code reader, digital volt/ohmmeter, a specialized diagnostic CAN scanner, a CAN Bus system wiring diagram, and an auxiliary ground cable. In addition, the mechanic must perform the following steps:
Mechanics often make the mistake of repairing stored trouble codes that are present in response to a P0649 trouble code as opposed to the real issue. This leads to an unsuccessful repair and the trouble code returning.
Usually the worst that happens when this trouble code is stored are an illuminated or non-working speed control lamp, as well as a lit Check Engine Light.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.