P1585

Circuit Description
The Cruise Control module pulls the Cruise Inhibit circuit up to approximately 12 volts. When the PCM determines that cruise control is allowed, the PCM grounds the Cruise Inhibit circuit. The Cruise Control module detects the low voltage signal and enables the system. The PCM grounds the cruise inhibit circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. If the fault detection circuit senses a voltage Other than what is expected, this DTC will set.

Conditions for Running the DTC
^ The ignition voltage is between 9.0 and 18.0 volts.
^ The engine speed is greater than 80 RPM.
^ The PCM Driver transitions from On to Oft or from Off to On.

Conditions for Setting the DTC
^ A short to ground, an open circuit, or a short to battery voltage is detected on the control circuit.
^ Condition present for at least 30 seconds.

Action Taken When the DTC Sets
^ The PCM stores the DTC information into memory when the diagnostic runs and fails.
^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The PCM records the operating conditions at the time the diagnostic tails. The PCM stores this information in the Failure Records.

Conditions for Clearing the MIL/DTC
^ A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any Other non-emission related diagnostic.
^ A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.
^ Use a scan tool in order to clear the MIL/DTC.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Diagnostic Aids

Notice: Use the Connector Test Adapter Kit J 35616-A for any test that requires probing the following items:
^ The PCM harness connectors
^ The electrical center fuse/relay cavities
^ The component terminals
^ The component harness connector
Using this kit will prevent damage caused by the improper probing of connector terminals.
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.


Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
2. Normally, ignition feed voltage should be present on the control circuit with the PCM disconnected and the ignition turned ON.
3. Checks for a shorted component or a short to B+ on the control circuit. Either condition would result in a measured current of over 500 milliamps. Also checks for a component that is going open while being operated, resulting in a measured current of 0 milliamps.
4. Checks for a short to voltage on the control circuit.
15. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.