KOEO & KOER Codes (Hard Faults)
These codes indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE or Malfunction Indicator Light (MIL) to go on and remain on until fault is repaired. If KOEO or KOER codes are retrieved during KOEO SELF-TEST or KOER SELF-TEST, use DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS to find correct testing and repair procedures.
Continuous Memory Codes (Intermittent Faults)
These codes are used to diagnose intermittent problems. Continuous Memory Codes are retrieved after KOEO SELF-TEST. These codes indicate a fault that may or may not be present at time of testing.
After noting and/or repairing fault, clear codes from memory. See CLEARING CODES. Intermittent faults may be caused by a sensor, connector or wiring-related problem. See INTERMITTENTS in the TESTS W/O CODES - EEC-V (3.8L) article.
| CAUTION | Continuous Memory Codes should be recorded when retrieved. These codes may be used to identify intermittent problems that exist after all KOEO and KOER codes have been repaired. Some Continuous Memory Code faults may not be valid after KOEO and KOER codes are serviced. |
RETRIEVING CODES
Fault codes are retrieved from EEC-V system through Data Link Connector (DLC). (Scheme 57) Self-diagnostic test procedures are for use with New Generation Star (NGS) scan tester. If a generic scan tester is used, ensure tool is certified ODB-II standard.
| Application | Location |
|---|---|
| Mustang | Below Left Side Of Glove Compartment |
DATA LINK CONNECTOR (DLC) LOCATIONS
Scheme 57
Pass Codes
SYSTEM PASS indicates no diagnostic trouble codes were recorded in that portion of test. If SYSTEM PASS is not retrieved in KOEO SELF-TEST, codes retrieved during KOER SELF-TEST may not be valid.
Continuous Memory Codes
These codes result from information stored by PCM during continuous self-test monitoring. Use these codes for diagnosis only when KOEO SELF-TEST and KOER SELF-TEST result in SYSTEM PASS and all steps under QUICK TEST are successfully completed. These codes indicate faults previously recorded. Fault may or may not be currently present. See DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS.
VISUAL CHECK
Complete all steps in BASIC TESTING - 3.8L article before proceeding to self-diagnostic tests. Ensure vacuum hoses and EEC-V wiring harnesses are properly connected.
Apply parking brake, and place shift lever in Park (A/T) or Neutral(M/T) position. Block drive wheels. Turn off all electrical accessories.
EQUIPMENT HOOKUP
Connect appropriate test equipment to vehicle as follows
Generic Scan Tester
Ensure scan tester meets or exceeds OBD-II standard. Follow manufacturer's instructions to hook up equipment and record diagnostic trouble codes.
New Generation STAR (NGS) Tester
Turn ignition switch to OFF position. Connect adapter cable lead to diagnostic tester. (Scheme 58) Connect service connectors of adapter cable to vehicle Data Link Connector (DLC). Go to KOEO SELF-TEST.
Scheme 58
COMPUTED TIMING CHECK
Ensure all accessories are off and engine is at normal operating temperature. Disconnect SPOUT connector. Connect timing light. Using ignition switch, start engine. Ignition timing should be approximately 10 degrees BTDC (base timing). Reconnect SPOUT connector. Timing should advance from base timing. If timing is not as specified, check for causes of incorrect timing such as damaged Crankshaft Position (CKP) sensor. For additional procedure, see IGNITION CHECKS in the BASIC TESTING - 3.8L article.
ADDITIONAL SYSTEM FUNCTIONS
Note. Additional diagnostic system features are available to help diagnose driveability problems and service EEC-V systems.
FREEZE FRAME DATA MODE
This mode allows access to emission related data values from specific generic PIDs. These values are immediately stored in continuous memory when an emission related fault occurs. This provides a snapshot of the conditions that were present when the fault occurred. Freeze frame will be stored until PCM memory is erased.
To access FREEZE FRAME DATA MODE, turn ignition switch to OFF position. Ensure test equipment is properly attached. Program scan tester using the following steps
- Select vehicle and engine selection menu (optional). see scheme 3
- Select year, engine, model and any additional information requested by scan tester (optional).
- Follow operating instructions from scan tester menu.
- Select GENERIC OBD-II FUNCTIONS. Press CONT button if OBD-II monitors are not complete.
- Turn ignition on.
- Select FREEZE FRAME PID TESTS.
FAILURE MODE EFFECTS MANAGEMENT (FMEM)
FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to monitor sensor. If faulty sensor signals return to normal operating range, PCM will use those signals. Depending on specific failure, a fault code may be set in PCM memory.
Trip
A Trip, is a drive cycle with specific instructions for vehicle operation within a period of time. During a trip, all OBD-II components and monitors (except catalyst efficiency monitor) are tested at least once by the On Board Diagnostic system.
Note. The systems monitored during a trip are: Comprehensive Component Monitor, Misfire Monitor, EGR System Monitor, Heated Oxygen System Monitor, Adaptive Fuel Monitor And Secondary Air Injection Monitor.
Malfunction Indicator Lamp Function
Drive cycles and trips are used by OBD-II software strategy to control Malfunction Indicator Lamp (MIL) off function. MIL is illuminated whenever a DTC is stored in memory. MIL is turned off after 3 consecutive drive cycles or trips are completed, without identical fault being present. Number of drive cycles or trips, varies with each system monitor. See appropriate test in this section.
OBD-II Drive Cycle
An OBD-II drive cycle is a specific method used to perform all trip monitor tests. (Scheme 59)
Scheme 59
Comprehensive Component Monitor
Comprehensive component DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated after comprehensive component monitor detects a malfunction during 2 consecutive drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
EGR Monitor
EGR system DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated after EGR system monitor detects a malfunction during 2 consecutive drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
Fuel System Monitor
Fuel system DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated after fuel system monitor detects a malfunction during 2 consecutive drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
Catalyst Efficiency Monitor
Catalyst Efficiency DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated after catalyst efficiency monitor detects a malfunction during 3 consecutive drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
Heated Oxygen Sensor Monitor
Heated Oxygen Sensor (HO2S) system DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated after HO2S monitor detects a malfunction during 2 consecutive drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
Misfire Detection Monitor
When a misfire that could cause catalytic convertor damage is detected, DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated. If misfire that could cause catalytic convertor damage or cause emissions failure is detected MIL will remain on continuously and DTC will be stored after 2 separate drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
Secondary Air Injection Monitor
Secondary Air Injection (AIR) DTC is stored in memory, and Malfunction Indicator Light (MIL) is illuminated after AIR monitor detects a malfunction during 2 consecutive drive cycles. MIL is turned off after 3 consecutive trips, during which no malfunction is detected that would normally trigger a DTC. DTC is erased from memory after 40 warm-up cycles, during which no malfunction is detected. DTC can also be erased, by using Powertrain Control Module (PCM) reset function on NGS tester.
SUMMARY
If no diagnostic trouble code is present but driveability problem still exists, see the TESTS W/O CODES - EEC-V (3.8L) article for symptom diagnosis or intermittent diagnostic procedures.
Scheme 60
Scheme 61
Scheme 62
Scheme 63
DTC REFERENCE CHART (CODES: No Codes-PO155). Scheme 64
DTC REFERENCE CHART (CODES PO156-PO325). Scheme 65
DTC REFERENCE CHART (CODES PO326-PO505). Scheme 66
DTC REFERENCE CHART (CODES PO603-PO756). Scheme 67
DTC REFERENCE CHART (CODES PO760-PO1150). Scheme 68
DTC REFERENCE CHART (CODES PO1151-PO1364). Scheme 69
DTC REFERENCE CHART (CODES PO1390-PO1500). Scheme 70
DTC REFERENCE CHART (CODES PO1505-PO1747). Scheme 71
DTC REFERENCE CHART (CODES PO1749-PO1787). Scheme 72
CIRCUIT TESTS
Note. A breakout box, connected to vehicle harness at PCM, is necessary to perform most circuit tests. References to Test Pin No. found in CIRCUIT TEST steps refer to test terminals on manufacturer's breakout box. Circuit diagrams at beginning of each test identify circuit and wire colors.
HOW TO USE CIRCUIT TESTS
1) Ensure all non-EEC related faults found while performing steps in the BASIC TESTING - 3.8L article have been corrected. DO NOT perform any CIRCUIT TEST unless specifically instructed by a QUICK TEST procedure. Follow each test step in order until fault is found. DO NOT replace any part unless directed to do so. When more than one code is retrieved, start with first code displayed.
2) CIRCUIT TESTS ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, opens or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with ignition on or as specified in CIRCUIT TESTS.
3) DO NOT measure voltage or resistance at PCM. DO NOT connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector (wiring harness side). Isolate both ends of a circuit and turn ignition off when checking for shorts or continuity, unless instructed otherwise.
4) Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, check all component connections and repeat QUICK TEST.
5) An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too high for some items in EEC-V system. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10,000 ohms to ground, unless stated otherwise in CIRCUIT TEST.
Note. In following tests, circuit diagrams and illustrations are courtesy of Ford Motor Co.
Transmission Drive Cycle
Record codes and clear PCM memory. Warm engine to normal operating temperature. With vehicle stopped on open road, place gear selector in Drive and accelerate heavily to 35 MPH. Stop vehicle and turn ignition off.
1) Continuous Memory DTC P0715 & P0720 Perform TRANSMISSION DRIVE CYCLE. Perform KOEO self-test. If Continuous Memory DTC P0715 or P0720 is present, go to next step. If no codes are present, go to CIRCUIT TEST Z.
2) Check OSS/TSS Circuit Continuity Turn ignition off. Disconnect OSS/TSS sensor. Disconnect PCM 104-pin connector. Inspect pins for damage and repair if necessary. Install EEC-V Breakout Box (014-00959), leaving PCM disconnected. Measure resistance between breakout box test pin No. 84 (OSS/TSS) and OSS/TSS terminal at OSS/TSS wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST.
3) Check OSS/TSS Circuit For Short To Ground Leave ignition off and OSS/TSS sensor disconnected. Measure resistance between test pins No. 51 (GND) and 84 at breakout box. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, repair faulty resistor or short circuit and repeat QUICK TEST.
4) Check OSS/TSS Circuit For Short To Power Leave ignition off and OSS/TSS sensor disconnected. Measure resistance between test pins No. 71 (VPWR) and 84 at breakout box. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short in OSS/TSS circuit and repeat QUICK TEST.
5) Check OSS/TSS Sensor Resistance Leave ignition off and OSS/TSS sensor disconnected. Measure resistance between OSS/TSS sensor terminals. OSS sensor resistance should be 450-750 ohms. TSS sensor resistance should be 64-200 ohms. If resistance is not as specified, replace OSS/TSS sensor. If resistance is as specified, check transmission for mechanical faults. If transmission is okay, replace PCM and repeat QUICK TEST.