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SYSTEM TESTS

WARNING: APPLY PARKING BRAKE AND/OR BLOCK WHEELS BEFORE PERFORMING ANY TEST WITH THE ENGINE OPERATING.

OBTAINING FAULT CODES

(1)Connect DRBII to the diagnostic connector located in the engine compartment (Fig. 21 or Fig. 22).

(2)Start the engine if possible, cycle the trans mission selector and the A/C switch if applicable. Shut off the engine.

(3)Turn the ignition switch on, access Read Fault Screen. Record all the fault messages shown on the DRBII. Observe the check engine lamp on the instrument panel. The lamp should light for 2 seconds then go out (bulb check).

Fault code erasure: access erase fault code data.

STATE DISPLAY TEST MODE

The switch inputs used by the engine controller have only two recognized states, HIGH and LOW. For this reason, the engine controller cannot recognize the difference between a selected switch position versus an open circuit, a short circuit, or a defective switch. If the change is displayed, it can be assumed that the entire switch circuit to the engine controller is functional. From the state display screen access either State Display Inputs and Outputs or State Display Sensors.

STATE DISPLAY INPUTS AND OUTPUTS

Connect the DRB II tester to the vehicle and access the State Display screen. Then access Inputs and Outputs. The following is a list of the engine control system functions accessible through the Inputs and Outputs screen.

Park/Neutral Switch (automatic transmission only) Speed Control Resume

Brake Switch

Speed Control On/Off Speed Control Set A/C Switch Sense

Z2 Voltage Sense

S/C Vent Solenoid S/C Vacuum Solenoid A/C Clutch Relay Baro Read Solenoid Wastegate Solenoid Auto Shutdown Relay Radiator Fan Relay Purge Solenoid Check Engine Lamp

FUEL SYSTEMS 14 - 67

STATE DISPLAY SENSORS

Connect the DRB II tester to the vehicle and access the State Display screen. Then access Sensor Display. The following is a list of the engine control system functions accessible through the Sensor Display screen.

Battery Temp Sensor

Oxygen Sensor Signal

Coolant Temperature

Coolant Temp Sensor Throttle Position Minimum Throttle

Detonation (Knock) Sensor Signal Battery Voltage

MAP Sensor Reading

AIS Motor Position

Adaptive Fuel Factor

Barometric Pressure

Min Airflow Idl Spd Engine Speed

Fault #1 Key-On Info

Module Spark Advance Cyl 1 Knock Retard Cyl 2 Knock Retard Cyl 3 Knock Retard Cyl 4 Knock Retard Boost Pressure Goal Speed Control Target Fault #2 Key-on Info Fault #3 Key-on Info Speed Control Status Charging System Goal Theft Alarm Status Wastegate Duty Cycle Map Sensor Voltage Vehicle Speed

Oxygen Sensor State Baro Read Update MAP Gauge Reading Throttle Opening Total Spark Advance

CIRCUIT ACTUATION TEST MODE

The purpose of the circuit actuation test mode is to check for the proper operation of output circuits or devices which the engine controller cannot internally recognize. The engine controller can attempt to activate these outputs and allow an observer to verify proper operation. Most of the tests available in this mode provide an audible or visual indication of device operation (click of relay contacts, spray fuel, etc.). With the exception of an intermittent condition, if a device functions properly during its test, it can be assumed that the device, its associated wiring, and its driver circuit are in working order.