Diagnostic Tool Setup and Functionality
The diagnostic tool must be connected to the data link connector (DLC) for communication with the vehicle.
The DLC is located in the passenger compartment. It is attached under the instrument panel and accessible from the driver seat.
The DLC is rectangular in design and capable of accommodating up to 16 terminals. The connector has keying features to allow easy connection. The vehicle connector and the diagnostic tool connector have a latching feature that makes sure the diagnostic tool connector remains mated when properly connected.
The required diagnostic tool functions are described below
- Monitor, record, and playback of PIDs
- Freeze frame PID data
- Diagnostic test modes; self-test, clear diagnostic trouble codes (DTCs)
- Output test mode
- Resetting keep alive memory (KAM)
- Diagnostic monitoring test results for OBD on-board monitors
- On-board system readiness (OBD monitor completion status)
Some of these functions are described in this article. Refer to the diagnostic tool manufacturer's manual for specific information on diagnostic tool setup, operation, and specific cables and/or adapters required.
Retrieve/Clear Continuous Diagnostic Trouble Codes (DTCs)
Retrieve/clear continuous DTCs is a functional test of the PCM. DTCs can be retrieved or cleared with the key on and the engine off or running. Unlike the KOEO and KOER self-tests, which can only be activated on demand, the continuous monitor is always active in monitoring the system. When a fault is detected, a DTC is stored in memory to be retrieved at a later date, making it possible to diagnose intermittent faults. A P1000 DTC may be the only DTC displayed, indicating an incomplete on-board diagnostic (OBD) drive cycle (more drive time needed). The fuel injection control module (FICM) continuously monitors the injector circuits for a fault. The FICM sends failure information through the controller area network (CAN) and a PCM DTC is set.
Key On Engine Off (KOEO) On-Demand Self-Test
The KOEO on-demand self-test is an on-demand functional test of the PCM carried out with the key on and the engine off. This test checks that all inputs and outputs (circuits, sensors, regulators, relays, and solenoids) connected to the PCM are electrically operating without fault.
Key On Engine Off (KOEO) Injector Electrical Self-Test (Click Test)
The KOEO injector electrical self-test (click test) is an on-demand functional test of the fuel injection control module (FICM) carried out with the key on and the engine off. This test determines if the injector circuits and solenoids are electrically operating without fault. All injectors click (audible feedback of the injector solenoids energizing the injector valves) together. Then each injector, 1 through 8, is cycled approximately one second in sequence. This process is repeated 3 times during the entire test. If a fault is detected by the FICM, a CAN message is sent to the PCM. Corresponding fault DTCs are displayed at the end of the self-test.
Scheme 172
Key On Engine Running (KOER) On-Demand Self-Test
The KOER on-demand self-test is an on-demand functional test of the PCM carried out with the engine running. Temperature is not a factor, but the air conditioning (A/C) must be turned off. A check is made on the injection control pressure (ICP), variable geometry turbocharger (VGT), and exhaust gas recirculation (EGR) systems. During this test, the engine RPM may vary. A fault must be present at the time of testing for the KOER on demand self-test to detect a fault. If a fault is detected, a DTC is output on the data link at the end of the test when requested by a diagnostic tool. Only a hard fault code DTC is displayed.
Key On Engine Running (KOER) Glow Plug Monitoring Self-Test
The KOER glow plug monitoring self-test is an on-demand functional test of the glow plug system carried out with the engine running and the A/C off. Battery voltage must be maintained at 10-14 volts during this test. If necessary, apply the accelerator pedal to increase voltage to the specified level. The PCM activates the glow plug control module (GPCM) and monitors the glow plug circuits. A fault must be present at the time of testing for the test to detect a fault. DTCs are sent to the PCM on the diagnostic line and then output to the diagnostic tool.
KOEO On-Demand Self-Test
Note. It is necessary to wait 4 seconds after key on to initiate the KOEO self-test. Failure to do so results in a test fail powertrain control module (PCM) message to be displayed.
Connect the diagnostic tool. Turn off all accessories. If the vehicle is equipped with a power take-off (PTO) system or auxiliary idle control, it must be turned off to carry out the self-tests.
- Carry out the necessary vehicle preparation and visual inspection. Refer to «QUICK TEST OPERATION.»(ref-232983-S35877238962006052300000)
- Refer to the manufacturer's manual for diagnostic tool instructions.
Note. The following steps must be carried out for the PCM and the transmission control module (TCM).
- Key on, engine off.
- Select KOEO on-demand self-test.
- Wait 4 seconds for the PCM and the fuel injection control module (FICM) to initialize completely.
- Follow the operating instructions from the menu.
- Record the diagnostic trouble codes (DTCs) and follow the appropriate pinpoint test.
- After the test, cycle the key to the OFF position before running other tests or driving the vehicle.
If carrying out repeated self-tests, it may be necessary to unplug the glow plug control module (GPCM) to maintain battery voltage. Ignore any glow plug codes while the GPCM is unplugged.
KOER On-Demand Self-Test
Connect the diagnostic tool. Turn off all accessories. Turn the air conditioning (A/C) off. If the vehicle is equipped with a power take-off (PTO) system or auxiliary idle control, it must be turned off to carry out the self-tests.
Note. The engine may run rough during this test.
- Carry out the necessary vehicle preparation and visual inspection. Refer to «QUICK TEST OPERATION.»(ref-232983-S35877238962006052300000)
- Refer to the manufacturer's manual for diagnostic tool instructions.
Note. The following steps must be carried out for the powertrain control module (PCM) and transmission control module (TCM).
- Select KOER on-demand self-test.
- Follow the operating instructions from the menu.
- Record the diagnostic trouble codes (DTCs) and follow the appropriate pinpoint test.
- After the test, cycle the key to the OFF position before running other tests or driving the vehicle.
KOEO Injector Electrical Self-Test (Click Test)
Note. If no diagnostic trouble codes (DTCs) are present and the KOEO injector electrical self-test (click test) aborts while trying to activate, refer to INJECTOR INTERRUPT FOR ENHANCED DIAGNOSTICS .
Connect the diagnostic tool. Turn off all accessories. Turn the air conditioning (A/C) off. If the vehicle is equipped with a power take-off (PTO) system or auxiliary idle control, it must be turned off to carry out the self-tests.
- Carry out the necessary vehicle preparation and visual inspection. Refer to «QUICK TEST OPERATION.»(ref-232983-S35877238962006052300000)
- Refer to the manufacturer's manual for diagnostic tool instructions.
- Select KOEO injector electrical self-test.
- Follow the operating instructions from the menu.
- Record the DTCs and follow the appropriate pinpoint test.
- After the test, cycle the key to the OFF position before running other tests or driving the vehicle.
KOER Glow Plug Monitoring Self-Test
Connect the diagnostic tool. Turn off all accessories. Turn the air conditioning (A/C) off. If the vehicle is equipped with a power take-off (PTO) system or auxiliary idle control, it must be turned off to carry out the self-tests.
Note. When running this self-test, the battery voltage must not decrease to less than 10 volts or exceed 14 volts. Make sure that the batteries are OK and the charging system is working properly. If necessary, apply the accelerator pedal to maintain system voltage.
- Carry out the necessary vehicle preparation and visual inspection. Refer to «QUICK TEST OPERATION.»(ref-232983-S35877238962006052300000)
- Using a digital multimeter connected to the battery, monitor the voltage. It may be necessary to increase the RPM to maintain the voltage.
- Start the engine.
- Set the parking brake and place the transmission in PARK (automatic), or NEUTRAL (manual).
- Refer to the manufacturer's manual for diagnostic tool instructions.
- Select KOER glow plug monitoring self-test.
- Follow the instructions on the screen.
- Maintain the system voltage until the test is complete.
- Record the DTCs and follow the appropriate pinpoint test.
Accessing On-Board System Readiness (OSR) Test
- Refer to the manufacturer's manual for diagnostic tool instructions.
On-Board Diagnostic (OBD) PID Data Monitor
The PID monitor for OBD offers real time evaluation of several emissions-related parameters. Most of these are related to the HO2S, for which the diesel has no equivalent. The only parameters which apply to 6.0L diesel applications are DTC CNT, IAT, LOAD, MAP, MIL, RPM, and VSS.
Clear The Continuous Diagnostic Trouble Codes (DTCs) And Reset The Emission Monitors Information in The Powertrain Control Module (PCM)
Note. Clear the continuous diagnostic trouble codes (DTCs) and reset the emission monitors information in the powertrain control module (PCM) was previously called PCM reset.
Intermittent Diagnostic Techniques
Intermittent diagnostic techniques help find and isolate the root cause of intermittent faults associated with the powertrain control module (PCM). The material is organized to help find the fault and carry out the repair. There are examples that illustrate the diagnostic techniques. The process of finding and isolating an intermittent starts with recreating a fault symptom, accumulating PCM data, comparing that data to typical values, and analyzing the results.
Before proceeding, make sure that
- Customary mechanical system tests and inspections do not reveal a problem. (Remember, mechanical component problems can make a PCM system react abnormally.)
- Review the Technical Service Bulletins (TSBs), if available.
- The Quick Test and associated pinpoint diagnoses have been completed without finding a fault, and the symptom is still occurring.