DTC P1566 Engine RPM Too High - Cruise Control Disabled. Cadillac Concours 1997

For 1990-2009 cars
Engine Controls Components
VSS/ Vehicle Speed Output/ SMCC
OBD II Symbol Description Notice
ESD Notice
ESD Notice
ESD Notice
ESD Notice

### Circuit Description

This diagnostic test will set if engine speed exceeds 5975 RPM while cruise control is engaged. This may occur on slippery pavement, extended wide open throttle acceleration, or for some mechanical problems (such as transaxle slippage). Under these conditions, DTC P1566 will set and should be considered normal. The driver should be advised why the cruise disengaged. Clear the DTC and road test vehicle to verify normal operation.

### Conditions for Setting the DTC

#### Test Conditions

• | Driver not manually controlling throttle position.

• | Cruise control engaged.

#### Failure Condition

Engine speed 5975 RPM or greater for 0.5 second.

### Action Taken When the DTC Sets

• | PCM disables cruise control.

• | The Malfunction Indicator Lamp (MIL) will not illuminate.

• | No message will be displayed.

### Conditions for Clearing the DTC

• | A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.

• | A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

• | Use a scan tool to clear DTCs.

• | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

### Diagnostic Aids

Reviewing the Failure Rec. may help diagnose an intermittent failure by showing how long ago and under what conditions the DTC set.

Clear the DTC and operate the vehicle under the conditions in which the DTC set if a fault condition is suspected.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to A Powertrain On Board Diagnostic (OBD) System Check
2 | Since most occurrences of DTC P1566 are caused by wheelspin due to icy, wet or slippery conditions, check with the customer to verify the conditions under which the DTC set. Did the road conditions cause this DTC to set? | -- | Go to Step 4 | Go to Step 3
3 | Is a mechanical problem (such as transaxle slippage) present? | -- | Repair mechanical problem | Fault not present. Refer to Diagnostic Aids
4 | Explain system operation to the customer and clear this DTC. Is the repair complete? | -- | System OK | --