DIAGNOSTIC TEST MODE IÐBULB CHECK
In this mode, the MALFUNCTION INDICATOR LAMP on the instrument panel should stay ON. If it remains
OFF, check the bulb. (See the WARNING LAMPS AND CHIME in the EL section. Or see EC-173, 174.)
DIAGNOSTIC TEST MODE IÐMALFUNCTION WARNING
MALFUNCTION
INDICATOR LAMPCondition
ON When the malfunction is detected (Refer to EC-1.) or the ECM's CPU is malfunctioning.
OFF No malfunction
lThese Diagnostic Trouble Code Numbers are clarified in Diagnostic Test Mode II (SELF-DIAGNOSTIC
RESULTS).
DIAGNOSTIC TEST MODE IIÐSELF-DIAGNOSTIC RESULTS
In this mode, a diagnostic trouble code is indicated by the number of blinks of the MALFUNCTION INDICA-
TOR LAMP as shown below.
Long (0.6 second) blinking indicates the number of ten digits, and short (0.3 second) blinking indicates the
number of single digits. For example, the malfunction indicator lamp blinks 4 times for about 5 seconds (0.6
sec x 8 times) and then it blinks three times for about 1 second (0.3 sec x 3 times). This indicates the DTC
``43'' and refers to the malfunction of the throttle position sensor.
In this way, all the detected malfunctions are classified by their diagnostic trouble code numbers. The DTC
``55'' refers to no malfunction. (See DIAGNOSTIC TROUBLE CODE INDEX, refer to page EC-1.)
How to erase diagnostic test mode II (Self-diagnostic results)
The diagnostic trouble code can be erased from the backup memory in the ECM when the diagnostic test
mode is changed from Diagnostic Test Mode II to Diagnostic Test Mode I. (Refer to ``HOW TO SWITCH
DIAGNOSTIC TEST MODES''.)
lIf the battery terminal is disconnected, the diagnostic trouble code will be lost from the backup
memory within 24 hours.
lBe careful not to erase the stored memory before starting trouble diagnoses.
lIf the MIL blinks or ``NATS MALFUNCTION'' is displayed
on ``SELF-DIAG RESULTS'' screen, perform self-diag-
nostic results mode with CONSULT using NATS pro-
gram card (NATS-E940). Refer to EL section.
lConfirm no self-diagnostic results of NATS is displayed
before touching ``ERASE'' in ``SELF-DIAG RESULTS''
mode with CONSULT.
lWhen replacing ECM, initialisation of NATS V2.0 system
and registration of all NATS V2.0 ignition key IDs must
be carried out with CONSULT using NATS program card
(NATS-E940).
Therefore, be sure to receive all keys from vehicle
owner.
Regarding the procedures of NATS initialisation and
NATS ignition key ID registration, refer to CONSULT
operation manual, NATS V2.0.
SEF212NA
SEF288Q
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
Malfunction Indicator Lamp (MIL) (Cont'd)
EC-43
Voltage check method
1. Remove the blown fuse and disconnect all loads (i.e. SW1 open, relay disconnected and solenoid dis-
connected) powered through the fuse.
2. Turn the ignition key to the ON or START position. Verify battery voltage at the B
+side of the fuse ter-
minal (one lead on the B
+terminal side of the fuse block and one lead on a known good ground).
3. With SW1 open and the DMM leads across both fuse terminals, check for voltage.
voltage; short is between fuse block and SW1 (point A).
no voltage; short is further down the circuit than SW1.
4. With SW1 closed, relay and solenoid disconnected and the DMM leads across both fuse terminals, check
for voltage.
voltage; short is between SW1 and the relay (point B).
no voltage; short is further down the circuit than the relay.
5. With SW1 closed, relay contacts jumped with fused jumper wire check for voltage.
voltage; short is down the circuit of the relay or between the relay and the disconnected solenoid
(point C).
no voltage; retrace steps and check power to fuse block.
GROUND INSPECTION
Ground connections are very important to the proper operation of electrical and electronic circuits. Ground
connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can
become an unwanted resistance. This unwanted resistance can change the way a circuit works.
Electronically controlled circuits are very sensitive to proper grounding. A loose or corroded ground can
drastically affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit.
Even when the ground connection looks clean, there can be a thin film of rust on the surface.
When inspecting a ground connection follow these rules:
1. Remove the ground bolt screw or clip.
2. Inspect all mating surfaces for tarnish, dirt, rust, etc.
3. Clean as required to assure good contact.
4. Reinstall bolt or screw securely.
5. Inspect for ``add-on'' accessories which may be interfering with the ground circuit.
6. If several wires are crimped into one ground eyelet terminal, check for proper crimps. Make sure all of
the wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in
one eyelet make sure no ground wires have excess wire insulation.
SGI853
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-27
