GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Optra 🢒 Engine 🢒 Engine Controls - 1.8L (L79) 🢒 DTC P1607

Circuit Description

The engine control module (ECM) is the control center of the fuel injector system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the malfunction lamp indicator (MIL), and store a DTC or DTCs which identify the problem areas to aid the technician in making repairs. An electrically erasable programmable read only memory (EEPROM) is used to house the program information and the calibrations required for engine, transmission, and powertrain diagnostics operation. The ECM monitors EEPROM reset flag and lower power counter I/C overflow bits. If the ECM detects if lower power counter I/C has been reset due to battery disconnect or lower power counter I/C malfunction, the DTC will be stored.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1607 Control Module Ignition Off Timer Performance.

Conditions for Running the DTC
    • The ignition is ON with the engine OFF.
    • DTC P1607 runs once per drive cycle.

Conditions for Setting the DTC

The ECM detects a low power counter error for more than 3 seconds.

Action Taken When the DTC Sets
    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC
    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Turn the ignition OFF.

    2. Important: An intermittent ignition 1 voltage circuit and battery positive voltage circuit to the ECM, may cause this DTC to set.

  2. Replace the engine control module (ECM). Refer to Engine Control Module Replacement .

Is the repair complete?

Go to Step 3

--

3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 4

4

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK