Circuit Description
The powertrain control module (PCM) uses output driver modules (ODMs) to control many functions of the engine and the transaxle. The ODMs supply the ground path for a PCM controlled device when the PCM commands the device ON. Each ODM is able to control several outputs. Unlike the quad driver modules (QDMs) used in earlier model years, the ODMs are able to diagnose each output circuit. The PCM monitors the ODMs for circuit conditions that are incorrect for the commanded state of the ODM.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1585 Cruise Control Inhibit Output Circuit
Conditions for Running the DTC
| • | The engine speed is 450 RPM or more. |
| • | System voltage is between 8-16 volts. |
Conditions for Setting the DTC
| • | The PCM detects an improper voltage level on the output circuit that controls the cruise inhibit control circuit. |
| • | The condition exists for at least 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM will store the conditions present when the DTC sets as Failure Records data only. |
Conditions for Clearing the DTC
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC Information function. |
Diagnostic Aids
In order to determine whether an improper voltage level exists on the output circuit, the PCM compares the voltage level to the commanded state. For example, a failure condition exists if the PCM detects a low voltage level when the device is commanded OFF, or a high voltage level when the device is commanded ON.
If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Normally, ignition positive voltage should be present on the control circuit with the PCM disconnected and the ignition turned ON.
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This step tests for a short to voltage on the control circuit.
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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.
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 |
Does the voltage measure near the specified value? | B+ | Go to Step 3 | Go to Step 4 | |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 5 | |
4 | Test the cruise inhibit control circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
6 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
7 | Repair the short to voltage in the cruise inhibit control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 10 | -- |
8 | 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 10 | -- |
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 10 | -- | |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
