Incident Simulation Tests
INTRODUCTION
Sometimes the symptom is not present when the vehicle is brought in for service. If possible, re-create the
conditions present at the time of the incident. Doing so may help avoid a No Trouble Found Diagnosis. The
following section illustrates ways to simulate the conditions/environment under which the owner experiences
an electrical incident.
The section is broken into the six following topics:
+Vehicle vibration
+Heat sensitive
+Freezing
+Water intrusion
+Electrical load
+Cold or hot start up
Get a thorough description of the incident from the customer. It is important for simulating the conditions of
the problem.
VEHICLE VIBRATION
The problem may occur or become worse while driving on a rough road or when engine is vibrating (idle with
A/C on). In such a case, you will want to check for a vibration related condition. Refer to the illustration below.
Connectors & harness
Determine which connectors and wiring harness would affect the electrical system you are inspecting.Gen-
tlyshake each connector and harness while monitoring the system for the incident you are trying to dupli-
cate. This test may indicate a loose or poor electrical connection.
Hint
Connectors can be exposed to moisture. It is possible to get a thin ®lm of corrosion on the connector termi-
nals. A visual inspection may not reveal this without disconnecting the connector. If the problem occurs
intermittently, perhaps the problem is caused by corrosion. It is a good idea to disconnect, inspect and clean
the terminals on related connectors in the system.
Sensors & relays
Gentlyapply a slight vibration to sensors and relays in the system you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
SGI839
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
GI-21
***: Not applicable
NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Evaporative emission system EVAP system Evaporative emission control system
Exhaust gas recirculation valve EGR valve EGR valve
Exhaust gas recirculation control-BPT valve EGRC-BPT valve BPT valve
Exhaust gas recirculation control-solenoid valve EGRC-solenoid valve EGR control solenoid valve
Exhaust gas recirculation temperature sensor
EGRT sensor Exhaust gas temperature sensor
EGR temperature sensor
Flash electrically erasable programmable read
only memoryFEEPROM ***
Flash erasable programmable read only memory FEPROM ***
Flexible fuel sensor FFS ***
Flexible fuel system FF system ***
Fuel pressure regulator *** Pressure regulator
Fuel pressure regulator control solenoid valve *** PRVR control solenoid valve
Fuel trim FT ***
Heated Oxygen sensor HO2S Exhaust gas sensor
Idle air control system IAC system Idle speed control
Idle air control valve-air regulator IACV-air regulator Air regulator
Idle air control valve-auxiliary air control valve IACV-AAC valve Auxiliary air control (AAC) valve
Idle air control valve-FICD solenoid valve IACV-FICD solenoid valve FICD solenoid valve
Idle air control valve-idle up control solenoid
valveIACV-idle up control solenoid
valveIdle up control solenoid valve
Idle speed control-FI pot ISC-FI pot FI pot
Idle speed control system ISC system ***
Ignition control IC ***
Ignition control module ICM ***
Indirect fuel injection system IFI system ***
Intake air IA Air
Intake air temperature sensor IAT sensor Air temperature sensor
Knock *** Detonation
Knock sensor KS Detonation sensor
Malfunction indicator lamp MIL Check engine light
Manifold absolute pressure MAP ***
Manifold absolute pressure sensor MAPS ***
Manifold differential pressure MDP ***
Manifold differential pressure sensor MDPS ***
SAE J1930 TERMINOLOGY LIST
SAE J1930 Terminology List (Cont'd)
GI-44
