The following tests are performed with the engine OFF:
Section 8.3.1
Standard Test (KOEO Test)
Key Off Engine Off Tests (KOEO) are standard tests performed by the ECM. These tests are commanded by the technician using the Electronic Service Tool (EST) or using the Self Test Input (STI) push-button switch.
To perform the test using the EST, access the Engine Menu and select Diagnostic Tests. Then select Engine Off Tests. Depressing the Enter key will initiate the test.
To use the STI diagnostic push-button switch, depress the switch and hold in while turning the ignition switch to the ON position. Release the STI button after the key is in the ON position. Do not start the engine.
When the operator signals the test to begin, the ECM will perform internal tests of its processing components and internal memory.
It will automatically proceed to Output Circuit Check (OCC). This test checks output circuits to detect shorts or opens in the ECM, the harnesses or the actuators by operating the ECM output circuits and measuring each individual circuit response. If a circuit fails the test, a fault code will be logged in the memory.
The following circuits are checked by the ECM during the test:
- Engine Crank Inhibit (relay)
- Engine to Transmission Data Link
- Injection Pressure Regulator (IPR)
- Engine Fan
- Radiator Shutters
- Change Oil Light
- Oil/Water Light
- Engine Warning Light
- Vehicle Retarder Relay (VRE)
The output circuits check test only evaluate the electrical condition of the circuits involved and can only be performed by commanding the KOEO test. It does not evaluate the mechanical or hydraulic performance of any of the systems involved.
When the test is complete, the EST will display any faults that were found during the test. If the STI diagnostic switch was used to perform the test, the faults will be transmitted as Flash Codes, using the Oil Warning and Engine Warning lights.
The fault codes are read by counting the number of light flashes. The following sequence occurs.
- The Oil/Water light will flash one time. This indicates the beginning of Active fault codes.
- The Warn Engine light will flash repeatedly signaling the active fault codes. All codes are three digits. The number of flashes should be counted in sequence.
- At the end of each digit of the code there will be a short pause. For example, the code 232 will be sent as two flashes, a pause, three flashes, a pause, and two flashes.
- After each active code is displayed, the Oil/Water light will flash once to indicate the next active code.
- Once all active codes have been displayed, the Oil/Water will flash twice to indicate the beginning of Inactive codes.
- Inactive codes will be displayed in the same manner as active codes.
- Once the Inactive codes have been displayed, the Oil/Water will flash three times to indicate that all the stored fault codes have been displayed, END OF MESSAGE.
If it is necessary to repeat transmission of fault codes, press the STI button and all stored codes will be transmitted again, as described previously.
The STI button can be utilized to clear the Diagnostic Codes by:
- Depressing and holding the STI button
- Turning the ignition key ON
- Depressing and releasing the accelerator pedal three times
- Releasing the STI button
Section 8.3.2
Injector BUZZ Test, Engine Off
The purpose of the Engine Off Injector BUZZ Test is to diagnose electrical problems with the fuel delivery components. This test can only be accessed with the EST and only after an Engine Off Test or Standard Test has been performed.
Note: Before running this test, fault codes should be accessed, noted and erased. This will allow the faults found in this test to be displayed as Active Codes.
During the test, the ECM will actuate the injectors in numerical order, 1 through 6, not in firing order.
The ECM will monitor the electrical circuit operation of each injector and evaluate the performance of the injector’s solenoid and the electrical circuit operation. If an electronic component in the fuel system fails the expected parameters, an inactive fault code will be logged and transmitted tot he EST at the end of the test.
Note: The technician can monitor injector operation by listening to the sound each injector produces as it is activated by the ECM. However, in a hard start/no start condition where the oil may be very cold or thick, injectors may not be audible.
If the faults were not erased before this test, the faults found during this test will be displayed as Inactive Codes.
To read these fault codes after the test has been completed, access the Diagnostic Codes menu and read both active and inactive Codes.
Section 8.3.3
Output State Tests, Engine OFF
The Output State Test diagnoses the operation of the output signals and actuators. This test can only be performed by using the EST.
To run this test, select the Output State Test from the EST Engine Off Test menu. The test consists of two modes of operation.
In the OUTPUTS ARE LOW mode, the ECM will pull down the output voltage to their low state. This will actuate the output components that are controlled by the ECM grounding the circuits. The message: OUTPUTS ARE LOW will be displayed on the screen during this test.
In the OUTPUTS ARE HIGH mode, the ECM will pull up the output voltage to their high state. This will actuate the output components that are controlled by the ECM energizing the control circuits. During this test, OUTPUTS ARE HIGH will be displayed on the screen.
During this test, the output of the circuit in question can be monitored with a DVOM. The DVOM will measure a High or Low voltage state condition as the outputs are toggled. The actual voltage will vary with the circuit tested.
Note: The EST will only display OUTPUTS ARE HIGH or OUTPUTS ARE LOW. It will not display any voltages, etc. A breakout box and DVOM are required to monitor the suspected problem circuit or actuator.
Note: Faults will not be set by the ECM during this test.
The following actuators and signals are toggled high and low during the test:
- Engine Crank Inhibit (relay)
- Engine to Transmission Data Link
- Injection Pressure Regulator (IPR)
- Engine Fan
- Radiator Shutters
- Change Oil Light
- Oil/Water Light
- Engine Warning Light
- Vehicle Retarder Relay (VRE)
| Series 40E Troubleshooting Manual – 6SE241 |
| Generated on 10-13-2008 |