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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1585 Cruise Control Inhibit Output Circuit

Object Number: 475465 Size: SF
Engine Controls Components
Cruise Control Module and VSS
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

Output driver modules (ODMs) are used by the PCM to turn on many of the current-driven devices that control various engine and transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to whichever device the PCM is commanding ON. Unlike the quad driver modules (QDMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. If DTC P1585 is set, an incorrect voltage level has been detected on the stepper motor cruise control inhibit control circuit.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC
    • An improper voltage level has been detected on the cruise control inhibit control circuit.
    • The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets

    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC
    • A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

    • Poor connection at the PCM or the cruise control module
        Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
    • Damaged harness
        Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a digital multimeter connected between the cruise control inhibit control circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the stepper motor cruise control module. A change in voltage will indicate the location of the malfunction.

Reviewing the Fail 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

The numbers below refer to the step numbers on the Diagnostic Table.

  1. Normally, the ignition feed voltage should be present on the control circuit with the PCM disconnected and the ignition turned ON.

    2.

  2. This step 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. This step also checks for a component that is going open while being operated, resulting in a measured current of 0 milliamps.

    3.

  3. This step checks for a short to voltage on the control circuit.

    4.

  4. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, program the new PCM. Refer to PCM Replacement/Programming.

DTC P1585 -- Cruise Control Inhibit Control Circuit

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn OFF the ignition switch.
  2. Disconnect the PCM.
  3. Turn ON the ignition switch.
  4. Use a digital multimeter (DMM) in order to measure the voltage between the stepper motor cruise control module control circuit at the PCM harness connector and ground.

Is the voltage near the specified value?

B+

Go to Step 3

Go to Step 6

3

  1. Connect the DMM to measure the current between the cruise inhibit control circuit at the PCM harness connector and ground.
  2. Monitor the current reading on the DMM for at least 2 minutes.

Does the current reading remain between the specified values?

0.001-0.5 Amp

(1-500 mA)

Go to Step 11

Go to Step 4

4

  1. Turn OFF the ignition switch.
  2. Disconnect the stepper motor cruise control module (leave the PCM disconnected).
  3. Turn ON the ignition switch.
  4. Using the digital multimeter, measure the voltage between the cruise inhibit control circuit and ground.

Is voltage at the specified value?

0 V

Go to Step 10

Go to Step 5

5

Locate and repair the short to voltage in the cruise inhibit control circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 16

--

6
  1. Turn OFF the ignition switch.
  2. Check the ignition feed fuse for the stepper motor cruise control module.

Is the fuse blown?

--

Go to Step 7

Go to Step 8

7
  1. Locate and repair the short to ground in the ignition feed circuit for the stepper motor cruise control module. Refer to Repairing Connector Terminals in Wiring Systems.
  2. Replace the fuse.

Is the action complete?

--

Go to Step 16

--

8
  1. Disconnect the stepper motor cruise control module.
  2. Turn ON the ignition switch.
  3. Measure the voltage between the ignition feed circuit for the stepper motor cruise control module and ground.

Is the voltage near the specified value?

B+

Go to Step 9

Go to Step 13

9
  1. Check the cruise inhibit control circuit for an open or a short to ground.
  2. If you find a problem, repair the cruise inhibit control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find a problem?

--

Go to Step 16

Go to Step 10

10
  1. Check for the following conditions:
    2. • The cruise inhibit control circuit for a poor connection at the PCM.
    • The cruise inhibit control circuit for a poor connection at stepper motor cruise control module.
    • The stepper motor cruise control module ignition feed circuit for a poor connection at the stepper motor cruise control module.
  2. If you find a problem, replace any loose terminals as necessary. Refer to the following procedures:
    3. •  Connector Repairs in Wiring Systems.

Did you find a problem?

--

Go to Step 16

Go to Step 14

11
  1. Turn OFF the ignition switch.
  2. Reconnect the PCM.
  3. Disconnect the stepper motor cruise control module.
  4. Turn ON the ignition switch.
  5. Connect a test lamp between the cruise inhibit control circuit and the ignition feed circuit at the stepper motor cruise control module harness connector.
  6. Using the scan tool outputs test function, cycle the cruise inhibit output ON and OFF.

Does the test lamp flash ON and OFF?

--

Go to Diagnostic Aids

Go to Step 12

12
  1. Check the cruise inhibit control circuit for a poor connection at the PCM.
  2. If a problem is found, replace loose terminal. Refer to the following procedures:
    3. •  Connector Repairs in Wiring Systems.

Did you find a problem?

--

Go to Step 16

Go to Step 15

13

Locate and repair the open in the ignition feed circuit to the stepper motor cruise control module. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 16

--

14

Replace the stepper motor cruise control module. Refer to Cruise Control Module Replacement in Cruise Control.

Is the action complete?

--

Go to Step 16

--

15

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming

Is the action complete?

--

Go to Step 16

--

16

  1. Review and record the scan tool Fail Records data.
  2. Clear the DTCs.
  3. Operate the vehicle within the Fail Records conditions.
  4. Using a scan tool, monitor the Specific DTC info for DTC P1585 until the DTC P1585 test runs.

Does the scan tool indicate DTC P1585 failed this ignition?

--

Go to Step 2

System OK