Circuit Description
The engine control module (ECM) supplies either 5 or 12 volts to power various sensors or switches. The power is supplied through resistances in the ECM which are so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because the resistance is too low. The ECM controls output circuits such as the injectors, ISC, etc., by controlling the ground or the power feed circuit through transistors or through either of the following 2 devices:
| • | Output driver module (ODM) |
| • | Quad driver module (QDM) |
The input/output devices in the ECM include analog-to-digital converters, signal buffers, counters, and special drivers. The ECM controls most components with electronic switches which complete a ground circuit when turned ON. These switches are arranged in groups of 4 and 7, called either a surface-mounted quad driver module (QDM), which can independently control up to 4 output terminals, or QDMs which can independently control up to 7 outputs. Not all outputs are always used.
Conditions for Setting the DTC
| • | CPU A/D conversion is not completed and CPU is normal. |
| • | CPU internal error |
| • | A/D Conversion Error |
| • | The B+ voltage is higher than 10 volts after 2 seconds from resetting, starter switch OFF continues for 300 ms, timer pulse time abnormal continues over 50 times. |
| • | Charging voltage abnormal and battery voltage higher than 10 volts, except on over speed. |
| • | Charging Circuit Error |
Action Taken When the DTC Sets
| • | The ECM will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected. |
| • | The analog sensor is abnormal and runs in backup mode. |
| • | Charging stops, drivable by constant current only, and Injection amount limited to 80 mm³/seconds. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | 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 emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
DTC 0035 can be cleared by using the Clear Info on the scan tool or by using the Diag Clear Switch.
Diagnostic Aids
Inspect for the following conditions:
Poor connection at the ECM-Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Does DTC 0035 reset while the ignition is ON or the engine is running? | Go to Step 2 | Go to Diagnostic Aids |
2 | Clear the DTCs. Does DTC 0035 reset? | Go to Step 4 | Go to Step 3 |
3 | Inspect for radio wave interference. Ensure that there is not a wireless transmitter near the vehicle. Temporary poor connections at harness connector, noise due to harness GND floating, or ECM connector GND incomplete connection. Did you find and correct the condition? | System OK | Go to Step 4 |
4 |
Did you find and correct the condition? | Go to Step 6 | Go to Step 5 |
5 | Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data . Did you complete the replacement? | Go to Step 6 | -- |
6 |
Important: This trouble is a circuit problem within the ECM. If there is no problem in the power supply or GND, but the DTC will not clear, replace the ECM. Clear the DTCs. Does DTC 0035 reset? | Go to Step 1 | System OK |
