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TROUBLESHOOTING
Intermittent Failure
The term "intermittent failure" means a system may have had a failure, but it checks OK now. If the MIL does not come on, check
for poor contact or loose pins at all connectors related to the circuit that of the troubleshooting. If the MIL was on, but then went out,
the original problem may be intermittent.
Opens and Shorts
· ·
"Opens" and "Shorts" are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental
connection of a wire to ground or to another wire. In simple electronics, this usually means something will not work at all. With
ECMs this can mean something may work, but not the way it's supposed to.
If the Mil has come on
Refer to OTC READOUT (page 4-11 ).
If the Mil did not stay on
If the MIL did not stay on, but there is a driveability problem, do the SYMPTOM TROUBLESHOOTING (page 4-8).
SYSTEM DESCRIPTION
SELF-DIAGNOSIS SYSTEM
The PGM-FI system is equipped with the self-diagnostic system. When any abnormality occurs in the system, the ECM turns on the
MIL and stores a OTC in its erasable memory.
FAIL-SAFE FUNCTION
The PGM-FI system is provided with a fail-safe function to secure a minimum running capability even when there is trouble in the
system. When any abnormality is detected by the self-diagnosis function, running capability is maintained by pre-programed value
in the simulated program map. When any abnormality is detected in the fuel injector, the fail-safe function stops the engine to
protect it from damage.
OTC (Diagnostic Trouble Code)
• The OTC is composed of a main code and a sub code and it is displayed as a hyphenated number when retrieved from the ECM
with the MCS.
The digits in front of the hyphen are the main code, they indicate the component of function failure.
The digits behind the hyphen are the sub code, they detail the specific symptom of the component or function failure.
For example, in the case of the TP sensor:
- OTC 08 - 1 = (TP sensor voltage) - (lower than the specified value)
- OTC 08 - 2 = (TP sensor voltage) - (higher than the specified value).
• The ECT and TP sensor diagnosis will be made according to the voltage output of the affected sensor.
If a failure occurs, the ECM determines the Function Failure, compares the sensor voltage output to the standard value, and
then outputs the corresponding OTC to the MCS.
Mil Blink Pattern
• If the MCS is not available, OTC can be read from the ECM memory by the MIL blink pattern.
• The number of MIL blinks is the equivalent to the main code of the OTC (the sub code cannot be displayed by the MIL).
• The MIL will blink the current OTC, in case the ECM detects the problem at present, when the ignition switch is ON. The MIL will
stay ON when the engine speed is over 2000 rpm.
The MIL has two types of blinks, a long blink and short blink. The long blinking lasts for 1.3 seconds, the short blinking lasts for
0.3 seconds. One long blink is the equivalent of ten short blinks. For example, when two long blinks are followed by five short
blinks, the MIL is 25 (two long blinks= 20 blinks, plus five short blinks).
• When the ECM stores more than one OTC, the MIL will indicate them by blinking in the order from the lowest number to highest
number.
Mil Check
When the ignition switch is turned ON, the MIL will stay on for a few seconds, then go off. If the MIL does not come on, troubleshoot
the MIL circuit (page 4-48).
CURRENT OTC/FREEZE OTC
The OTC is indicated in two ways according to the failure status.
• In case the ECM detects the problem at present, the MIL will come on and the MIL will start to blink as its OTC. It is possible to
readout the MIL blink pattern as the current OTC.
• In case the ECM does not detect any problem at present but has a problem stored in its memory, the MIL will not light and blink.
If it is necessary to retrieve the past problem, readout the freeze OTC by following the OTC readout procedure (page 4-11 ).
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Table of Contents
Troubleshooting
