Circuit Description
The powertrain control module (PCM) has the ability to inhibit cruise control operation, if conditions exist that would make cruise control operation undesirable. The PCM will interrupt the ground on the cruise inhibit circuit to request that the cruise control be disengaged. The PCM also monitors the voltage on this circuit in order to determine if a fault exists.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1585 Cruise Control Inhibit Output Circuit
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The system voltage is between 9-16 volts. |
Conditions for Setting the DTC
| • | The PCM detects that an improper voltage exists on the cruise control inhibit signal circuit. |
| • | The above condition is present for at least 30 seconds. |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM stores the conditions which were present when the DTC set as Failure Records data only. This information is not stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
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.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the voltage measure near the specified value? | B+ | Go to Step 4 | Go to Step 3 |
3 | Test the cruise control inhibit signal circuit for an open, for a high resistance or for a short to ground between C103 and the cruise control module. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 |
4 | Test the cruise control inhibit signal circuit for an open, for a high resistance, or for a short to ground between C103 and the powertrain control module (PCM). Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 5 |
5 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
7 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the cruise control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
