What does it mean?
P1662 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cruise Lamp Control Circuit Malfunction .
Symptoms
- The cruise control indicator never lights when cruise is engaged
- Or the indicator stays lit continuously even with cruise off
- Cruise control may still work normally, since the fault is in the lamp circuit
- MIL on, with no change in how the engine runs
- On some vehicles the module disables cruise control as a precaution, so set speed will not hold
Likely causes
- Cruise indicator bulb or LED in the cluster open
- Open or shorted control wire between the module and the cluster indicator
- Corroded or loose terminals at the cluster or module connector
- Internal driver failure in the instrument cluster
- Failed indicator output driver in the control module
- Blown fuse on the indicator supply feed
- A cluster fitted from another vehicle that does not match this configuration
How to fix it
- Engage cruise control on a road test and confirm exactly how the indicator behaves
- Watch the cluster bulb check at ignition on to see whether the lamp can light at all
- Inspect and reseat the cluster connector, looking for corrosion and terminals that have lost tension
- Test the indicator control wire between module and cluster for continuity and for shorts to ground and battery voltage
- Check the fuse and power feed for the indicator circuit
- Replace a failed bulb or repair the cluster indicator circuit
- Replace the control module only after the cluster and wiring are proven good