DTC P1361 Ignition Control (IC) Circuit Low Voltage. Buick GL7 (Export) 2000

For 1990-2009 cars

### Circuit Description

The ignition control module (ICM) sends the signals that the PCM requires for fuel control and spark advance calculations. At the start of engine crank the ICM controls the spark advance. When the second 3X reference pulse is recognized by the powertrain control module (PCM), the PCM applies 5.0 volts to the bypass circuit. The voltage on the bypass circuit commands the ICM to switch the spark advance to PCM control. At this time, the ICM will remove the ground applied to the IC circuit. When the IC pulses are not grounded, the ICM can use the IC pulses to control the spark advance. A short in the IC circuit or an open or a short to ground in the bypass circuit will cause the PCM to set DTC P1361. The engine may be started but will run with the ICM controlling the spark timing.

### Conditions for Running the DTC

• | The engine speed is more than 600 RPM.

• | DTC P1351 is not set.

### Conditions for Setting the DTC

• | The PCM does not monitor IC pulses while IC mode spark advance is commanded.

• | The condition is present for 300 3X reference periods (100 crankshaft revolutions).

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.

• | 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.

### Diagnostic Aids

Inspect for the following conditions:

• | A poor connection at the PCM. Inspect the harness connectors for the following conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems:

- | Backed-out terminals

- | Improper mating

- | Broken locks

- | Improperly formed or damaged terminals

- | Poor terminal-to-wire connection

• | A damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the ICM, turn the ignition ON and observe a digital multimeter (DMM) connected between the IC circuit and B+ voltage while moving the connectors and the wiring harnesses related to the ICM. A change in the voltage indicates the location of the fault. Refer to Wiring Repairs in Wiring Systems .

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.

#### DTC P1361 - IC Circuit Not Toggling

Step | Action | Values | 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. Start the engine and allow the engine to idle for 2 minutes.
2. Observe the DTCs.

Is DTC P1361 set?

--

Go to Step 3

Go to Diagnostic Aids

3

1. Turn OFF the ignition.
2. Disconnect the PCM.
3. Install a test lamp between B+ voltage and the bypass circuit at the PCM harness connector.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 4

4

1. Turn ON the ignition.
2. With the test lamp connected between B+ voltage and the bypass circuit, measure the resistance between the IC circuit and the reference low circuit using a DMM.

Is the resistance more than the specified value?

5000 ohms

Go to Step 12

Go to Step 5

5

1. Turn OFF the ignition.
2. Probe the IC circuit with a test lamp connected to B+ voltage.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 6

6

1. Check the bypass circuit for an open.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 15

Go to Step 7

7

1. Check the bypass circuit for a poor terminal connection at the ICM.
2. If a problem is found, replace the faulty terminal. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Was a problem found?

--

Go to Step 15

Go to Step 14

8

1. Turn OFF the ignition.
2. Disconnect the ICM.
3. Turn ON the ignition.
4. Observe the test lamp connected between the bypass circuit and B+ voltage.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 14

9

1. Turn OFF the ignition.
2. Disconnect the ICM.
3. Turn ON the ignition.
4. Test the IC circuit for a short to voltage.
5. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 15

Go to Step 13

10 | Locate and repair short to ground in the IC circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 15 | --
11 | Locate and repair short to ground in the bypass circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 15 | --

12

1. Test the bypass circuit for a poor terminal connection at the PCM.
2. If a problem is found, repair as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Was a problem found?

--

Go to Step 15

Go to Step 13

13 | Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | Go to Step 15 | --
14 | Replace the ignition control module. Is the action complete? | -- | Go to Step 15 | --

15

1. Review and record the scan tool Failure Records data.
2. Clear the DTCs.
3. Operate the vehicle within the Failure Records conditions as noted.
4. Using a scan tool, monitor the Specific DTC info for DTC P1361.

Does the scan tool indicate DTC P1361 failed?

--

Go to Step 2

System OK