Diagnostic Tools
Below is an equipment list with corresponding part numbers
REQUIRED EQUIPMENT
- Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool with functionality described under Scan Tool Setup and Functionality.
- Rotunda Smoke Machine, Fuel Evaporative Emission System Tester 218-00001 (522) or equivalent.
RECOMMENDED EQUIPMENT
- Rotunda Vacuum/Pressure Tester 164-R0253 or equivalent. Range 0-101.3 kPa (0-30 in-Hg.) Resolution 3.4 kPa (1 in-Hg.)
- Fuel Pressure Test Kit 310-D009 (D95L-7211A) or equivalent.
- Fuel Pressure Test Adapter 310-180 or equivalent.
- Digital Multimeter (DMM) FLU77-4 or equivalent.
- Adjustable Ignition Spark Tester THX458 or equivalent.
- Non-powered test lamp.
- Fuel Pressure T Adapter (5/16") 310-D251 or equivalent
Scan Tool Setup And Functionality
Connect the scan tool to the data link connector (DLC) for communication with the vehicle.
The DLC is located on the driver side of the vehicle under the steering column. It is attached to 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 required scan tool functions are described below
- monitor, record, and playback of parameter identification (PID)
- freeze frame PID data
- diagnostic test modes; self-test, clear diagnostic trouble codes (DTCs)
- output state control (OSC)
- output test mode (OTM)
- resetting keep alive memory (KAM)
- diagnostic monitoring test results (mode 6) for on board diagnostic (OBD) monitors
- on board system readiness (OBD monitor completion status)
Some of these functions are described in this service information. Refer to the scan tool manufacturer's instruction manual for specific information on scan tool setup and operation.
Quick Test
The quick test is divided into 3 specialized tests
- Key On Engine Off (KOEO) On Demand Self-Test
- Key On Engine Running (KOER) On Demand Self-Test
- Continuous Memory Self-Test
The quick test checks the integrity and function of the electronic engine control (EEC) system and outputs the test results when requested by the scan tool. The quick test also provides a quick check of the powertrain control system, and is usually carried out at the start of each diagnostic procedure with all accessories off. The quick test is also carried out at the end of most pinpoint tests for verification of the repair and to make sure no other concerns are incurred while repairing a previous concern. A system pass is displayed when no diagnostic trouble codes (DTCs) are output and a scan tool communication error does not exist. System pass means that hardware monitored by the powertrain control module (PCM) is functioning within the normal operating limits. Only a system pass, a DTC, or an incomplete on board diagnostic (OBD) drive cycle is displayed.
For applications that use a stand-alone transmission control module (TCM) the PCM does not output TCM DTCs. For TCM self-test and diagnostics, refer to the appropriate Automatic Transaxle/Transmission article.
Key ON Engine OFF (KOEO) On Demand Self-Test
The KOEO on demand self-test is a functional test of the PCM carried out on demand with the ignition ON and the engine OFF. This test carries out checks on certain sensor and actuator circuits. A concern must be present at the time of testing for the KOEO self-test to detect the concern. When a concern is detected, a DTC is output on the data link at the end of the test as requested by the scan tool.
Key ON Engine Running (KOER) On Demand Self-Test
The KOER on demand self-test is a functional test of the PCM carried out on demand with the ignition ON, the engine running and the vehicle stopped. A check of certain inputs and outputs is made during operating conditions and at a normal operating temperature. The brake pedal position, transmission control, and the power steering tests are part of the KOER on demand self-test and must be carried out during this operation if applicable. These are described below. A concern must be present at the time of testing for the KOER on demand self-test to detect the concern. When a concern is detected, a DTC is output on the data link at the end of the test as requested by the scan tool.
Brake Pedal Position (BPP) Test
The BPP test checks the ability of the EEC system to detect a change of state in the BPP switch. The brake pedal is briefly applied and released on all vehicles equipped with a BPP input. This is done during a KOER on demand self-test.
Power Steering Pressure (PSP) Test
The PSP test checks the ability of the EEC system to detect a change in the power steering system fluid pressure. The steering wheel is briefly turned at least 1/4 of a revolution on vehicles equipped with a PSP switch or sensor. This is done during a KOER on demand self-test.
Transmission Control Switch (TCS) Test
The TCS test checks the ability of the EEC system to detect a change of state in the TCS. The switch is briefly cycled on all vehicles equipped with a TCS input. This is done during a KOER on demand self-test.
Continuous Memory Self-Test
The continuous memory self-test is a functional test of the PCM carried out under any condition (engine running or OFF) with the ignition ON. Unlike the KOEO and KOER self-tests, which can only be activated on demand, the continuous memory self-test is always active. A concern does not need to be present when accessing continuous memory self-test DTCs, making the test valuable when diagnosing intermittent concerns. The vehicle may need to be driven or the OBD drive cycle completed to allow the PCM to detect a concern. Refer to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE for more information. When a concern is stored in memory, a DTC is output on the data link when requested by the scan tool.
There are two types of continuous DTCs. The first type is an emission related code which illuminates the malfunction indicator lamp (MIL) in the instrument cluster. The second is a non-emission related, non-MIL DTC which does not illuminate the instrument cluster indicator.
For emission related MIL DTCs, the PCM stores the DTC in continuous memory when a concern is detected for the first time. At this point the DTC does not illuminate the MIL and is considered a pending code. The purpose of pending codes is to assist in repair verification by reporting a pending DTC after one drive cycle. If the same concern is detected after the next drive cycle, the emission related MIL DTC illuminates the MIL and sets both a confirmed MIL DTC and a permanent DTC. The MIL remains illuminated even if the concern is intermittent. A permanent DTC is stored until three consecutive passing drive cycles have been completed after a repair and the MIL turns off, or after a request to clear DTCs has been made using the scan tool and the next monitoring cycle has completed and passed for that DTC.
Confirmed emission related MIL DTCs and any non-emission related, non-MIL DTCs are erased approximately 40 vehicle warm-up cycles after the concern was last detected, or if the DTCs are cleared by the scan tool.
Pending emission related MIL DTCs that never detect a concern on a second consecutive drive cycle (and never illuminate the MIL) are not stored in memory for any number of vehicle warm-up cycles; they are immediately cleared when the next monitoring cycle has completed and passed for that DTC, or until a request to clear DTCs has been made by the scan tool.
Any scan tool that meets OBD requirements can access the continuous memory to retrieve emission related MIL DTCs. However, not all scan tools access pending and non-emission related, non-MIL DTCs in the same way.
During most diagnostic procedures in this service information, it is required that all DTCs be retrieved and cleared. Permanent DTCs cannot be directly cleared by the scan tool. When a scan tool clears DTCs, pending and confirmed DTCs are immediately cleared. Permanent DTCs will not clear until the next monitoring cycle has completed and passed for that DTC. For additional information, refer to POWERTRAIN CONTROL SOFTWARE , Permanent Diagnostic Trouble Code (DTC).
Diagnostic Monitoring Test Results Mode 6
Mode 6 allows access to the results of on board diagnostic (OBD) monitor diagnostic test results. The test values are stored at the time of the particular monitor completion. Refer to mode 6 on the scan tool for test information.
Intermittent Diagnostic Techniques
Intermittent diagnostic techniques help find and isolate the root cause of intermittent concerns associated with the electronic engine control (EEC) system. The information is organized to help find the concern and carry out the repair. The process of finding and isolating an intermittent concern starts with recreating a fault symptom, accumulating powertrain control module (PCM) data, and comparing that data to typical values, then analyzing the results. Refer to the scan tool manufacturer's instruction manual for the functions described below.
Before proceeding, be sure that
- Customary mechanical system tests and inspections do not reveal a concern. Mechanical component conditions can make a PCM system react abnormally.
- Technical Service Bulletins (TSBs) and On-line Automotive Service Information System (OASIS) messages, if available, are reviewed.
- Quick Test and associated diagnostic subroutines have been completed without finding a concern, and the symptom is still present.
Adaptive Fuel Diagnostic Trouble Code (DTC) Diagnostic Techniques
The Adaptive Fuel DTC Diagnostic Techniques help isolate the root cause of the adaptive fuel concern. Before proceeding, attempt to verify if any driveability concerns are present. These diagnostic aids are meant as a supplement to the pinpoint test steps in PINPOINT TESTS -- GASOLINE MODELS . For a description of fuel trim, refer to POWERTRAIN CONTROL SOFTWARE , Fuel Trim.
DTCs P0171 and P0174 System Too Lean Diagnostic Aids
Note. If the system is lean at certain conditions, then the LONGFT PID would be a positive value at those conditions, indicating that increased fuel is needed.
The ability to identify the type of lean condition causing the concern is crucial to a correct diagnosis.
DTCs P0172 and P0175 System Too Rich Diagnostic Aids
Note. If the system is rich at certain conditions, then the LONGFT PID would be a negative value at that airflow, indicating that decreased fuel is needed.
System rich concerns are caused by fuel system concerns, although the MAF sensor and base engine (for example, engine oil contaminated with fuel) should also be checked.