DTC P1362 Ignition Bypass Circuit Low Voltage. Buick GL7 (Export) 2000

For 1990-2009 cars

### Circuit Description

The ignition control module (ICM) sends the signals that the powertrain control module (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 PCM, the PCM applies 5.0 volts to the bypass circuit, commanding the ICM to switch the spark advance to PCM control. If the PCM detects a short to voltage in the bypass circuit, DTC P1362 will set. A short to ground in the IC circuit or the bypass circuit will cause both DTC P1352 and DTC P1362 to set. The engine will start and may run with the ICM controlling the spark timing.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

• | The PCM detects a short in the bypass circuit.

• | 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 connections

• | 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 malfunction. 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 P1362 - Bypass Circuit Shorted

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 | Is DTC P1361 also set? | -- | Go to Step 6 | Go to Step 3

3

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Turn ON the ignition switch.
4. Probe the bypass circuit with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 13

4

1. Turn OFF the ignition switch.
2. Leave the PCM disconnected.
3. Disconnect the ICM.
4. Turn ON the ignition switch
5. Probe the bypass circuit with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 12

5 | Locate and repair the short to voltage in the Bypass circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | --

6

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Disconnect the ICM.
4. Probe the IC circuit with a test lamp connected to B+ voltage.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 8

7 | Locate and repair the short to ground in the IC circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | --

8

1. Leave the ignition switch OFF.
2. Leave the PCM disconnected.
3. Leave the ICM disconnected.
4. Probe the bypass circuit with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 10

9 | Locate and repair the short to ground in the bypass circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | --

10

1. Leave the ignition switch OFF.
2. Leave the PCM disconnected.
3. Leave the ICM disconnected.
4. Check for a short between the IC circuit and the bypass circuit.
5. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 14

Go to Step 11

11

1. Leave the ignition switch OFF.
2. Reconnect the IC module.
3. Leave the PCM disconnected.
4. Turn ON the ignition switch.
5. Using a DMM, observe the resistance between the IC circuit and the reference low circuit while probing the bypass circuit with a test lamp connected to B+ voltage.

Does the resistance switch from less than the first value to more than the second value?

500 ohms

5000 ohms

Go to Step 13

Go to Step 12

12 | Replace the ignition control module. Is the action complete? | -- | Go to Step 14 | --
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 14 | --

14

1. Review and record the scan tool Failure Records data.
2. Clear the DTCs.
3. Operate the vehicle within the Failure Records conditions.
4. Using the scan tool, monitor the Specific DTC info for DTC P1362.

Does the scan tool indicate DTC 1362 failed this ignition?

--

Go to Step 2

System OK