DTC P1654 Cruise Control Inhibit Output Circuit. 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

The PCM contains chips called Output Driver Modules that provide 7 switchable ground outputs for operating solenoids, relays, telltales, and other devices. Each of these ground outputs has an internal fault line that feeds back to the PCM's microprocessor. When the output is OFF, the output driver should receive the 12 volts fed to the solenoid, relay, etc. When the output is ON, it should receive 0 volt since it is grounding the output. If it receives 0 volt when the output is OFF or 12 volts when the output is ON, it sets the fault line low. DTC P1654 is used to monitor the fault line of the cruise disable output to the cruise control module. The cruise control module sends 12 volts on CKT 83 to the PCM. The PCM will then ground this circuit to have cruise control module disengage if engaged or inhibit cruise operation if requested.

### Conditions for Setting the DTC

#### Test Conditions

• | DTC 1650 not set.

• | Engine running for at least 10 seconds.

#### Failure Condition

Fault line is low for 2 seconds.

### Action Taken When the DTC Sets

• | 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

Use the Failure Rec. to aid in diagnosing an intermittent fault. Use the data captured when the DTC set to determine if an open or shorted condition caused the DTC to set.

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

1. Turn the key ON.
2. Using a scan tool select Cruise Enable Driver display.

Does the display indicate OK?

--

Go to Step 6

Go to Step 3

3

1. Record the fluid life indexes, turn the key to LOCK and wait 30 seconds.
2. Disconnect PCM connector C1.
3. Turn the key ON.
4. Using DMM J 39200 measure the voltage to ground at PCM connector C1 terminal 26.

Is the voltage the same or more than the value specified?

10.0 volts

Fault not present. Refer to Diagnostic Aids

Go to Step 4

4

1. Turn the key to LOCK.
2. Disconnect the cruise control module.
3. Measure the resistance to ground at cruise control module connector terminal H (harness side).

Is the resistance the same or less than the value specified?

5 ohms

Go to Step 8

Go to Step 5

5 | Measure the resistance between cruise control module connector terminal H (harness side) and PCM connector C1 terminal 26. Is the resistance the same or less than the value specified? | 5 ohms | Go to Step 7 | Go to Step 9

6

1. Record the fluid life indexes, turn the key to LOCK and wait 30 seconds.
2. Disconnect PCM connector C1.
3. Disconnect the cruise control module.
4. Turn the key ON.
5. Using DMM J 39200 measure the voltage to ground at PCM connector C1 terminal 26.

Is the voltage the same or more than the value specified?

10.0 volts

Go to Step 10

Go to Step 14

7

1. Turn the key ON.
2. Measure the voltage to ground at cruise control module terminal F.

Is the voltage the same or more than the value specified?

10.0 volts

Go to Step 12

Go to Step 11

8 | Repair short to ground on the cruise inhibit output circuit. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --
9 | Repair the open in the cruise inhibit output circuit. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --
10 | Repair the short to voltage on the cruise inhibit output circuit. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --
11 | Repair open or short to ground (blown fuse) in the ignition feed to the cruise control module. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --

12

1. Check terminal contact at the cruise control module.
2. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 13

13 | Replace the cruise control module. Is the replacement complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --

14

1. Check terminal contact at the PCM.
2. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 15

15 | Replace the PCM. Refer to PCM Replacement/Programming . Is the replacement complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --