| Subject: | SES Light due to a P1400 DTC |
| Models: | 2007 Chevrolet Express Van |
| 2007 Chevrolet Silverado Classic (GMT800) |
| 2007 GMC Sierra Classic (GMT800) |
| with a 4.3L Engine (VIN X - RPO LU3) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
On rare occasions, a SES light may be experienced due to a P1400 DTC. Generally, most customers will not comment on any engine performance concerns even though a slight high idle may exist before the SES light illuminates. Generally, a P1400 will be
the only DTC present but in some instances, a P0507 DTC may also be stored with the P1400 DTC.
Recommendation/Instructions:
If the SI diagnostics do not isolate the cause of this P1400 DTC, perform the following recommendations as necessary:
| • | Command the engine speed from the lowest RPM to the highest RPM using the Tech 2. If abnormal operation is noted, diagnose and repair as necessary.
|
| • | Inspect the IAC motor circuits for possible shorts, poor connections, or poor terminal tension.
|
| • | Inspect the throttle cable and accelerator pedal for any type of concern that would cause a high idle concern.
|
| • | If there is no problem found, replace the throttle body for evaluation.
|
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
