Scan Tool Testing and Procedures

SCAN TOOL HOOK-UP

- Connect the scan tool to the diagnostic connector located in the engine compartment. The separate red clip is connected to the positive post of the battery.
- With the scan tool properly connected, all character positions on the display should briefly illuminate, and the copyright message should appear.
NOTE: At any time after the copyright screen, the user may press the F3 key for help.
- A commonly reported problem is that the scan tool screen is blank. If the screen is blank after the scanner is attached to the vehicle, do the following:
Make sure all cable connections are properly seated and fit snugly.
Make sure the cables are in good condition (no broken or shorted wires).
Make sure the cartridge is installed properly into the scan tool.
Try the scan tool on another vehicle. If the scan tool screen is still blank, have the unit repaired. If it now performs properly, continue with next step.

Data Link Connector Identification:

Make sure all cable connectors are in good condition (no flared or pushed out terminals). If the connector is good, continue with next step.

On-Board Diagnostic Connector Identification (Wire Color May Vary By Model):

Check the BK/WT wire in the diagnostic connector for continuity to ground.

ACCESSING AND DELETING FAULT CODES

CAUTION: Be sure to apply parking brake and/or block wheels before performing idle check or adjustment, or any engine running tests.

Diagnostic Connector:

1. Connect the scan tool to the diagnostic connector located in the engine compartment near the Single Board Engine Controller (SBEC).
2. If possible, START the engine, turn ON the air conditioning, and shift the transmission selector through all of the gears, returning to PARK (A/T) or NEUTRAL (M/T). Turn OFF the air conditioning and shut OFF the engine.
3. Turn ON the ignition switch and observe the CHECK ENGINE LAMP. It should light for approx. 2 seconds then go out. Access "Read Fault Data" on the scan tool and record any fault codes received.
NOTE: Refer to FAULT CODE IDENTIFICATION AND DIAGNOSTIC CHART REFERRAL for a listing of fault codes and related diagnostic routines.
4. Access "Erase Fault Data" and erase the fault code memory.


SWITCH TEST MODE

The switch inputs read by the Single Board Engine Controller (SBEC) have two recognized states (high and low). Therefore, the SBEC cannot determine the difference between a switch position and an open or shorted circuit, or a defective switch. By using the switch test mode, the present state of circuit at the SBEC is displayed. If the displayed state changes as the switch is toggled and the state corresponds to the operation of the switch, it can be assumed that the circuit is good. To use the switch test mode, access "Read Input States" on the scan tool.

The following circuits can be monitored in this mode:

- Air conditioning switch sense
- Brake switch
- PARK/NEUTRAL switch
- Speed control ON/OFF
- Speed control SET
- Speed control RESUME
- Z1 voltage sense

CIRCUIT ACTUATION TEST MODE

The circuit actuation test mode checks for the proper operation of output circuits and devices that the Single Board Engine Controller (SBEC) cannot test. The SBEC attempts to actuate these outputs and allows an observer to verify the operation of the component. Most of the checks in this mode provide an audible or visual indication of component operation. Unless an intermittent condition exists, if a device functions properly during its test, it can be assumed that the component and its related circuit are functioning properly. To enter circuit actuation mode, access "Actuate Solenoids/Rly" or actuate Outputs" on the scan tool.

The following components can be tested in this mode:

Actuate Solenoid/Rly

- Air conditioning clutch relay
- Auto shutdown relay
- EGR solenoid (California only)
- PTU solenoid (A/T only)
- Purge solenoid
- Radiator fan relay
- Speed control servo solenoids
- All solenoids/relays

Actuate Outputs

- AIS motor
- Alternator field
- Fuel injector #1
- Fuel injector #2
- Fuel injector #3
- Ignition coil #1
- Tachometer output

SENSOR TEST MODE

The sensor test mode reads the values of various sensors and displays them on the scan tool. They are displayed either in terms of Single Board Engine Controller (SBEC) input voltage, or they are converted into engineering units. This mode provides a means by which the integrity of individual sensor circuits can be checked whether the engine is running or not. To enter the sensor test mode, access "Read Sensor Voltage" or "Read Sensor Values" on the scan tool.

The following sensors can be read in this mode:

Read Sensor Voltage

- Battery temperature sensor
- Coolant temperature sensor
- Manifold Absolute Pressure (MAP) sensor voltage
- Minimum throttle
- Oxygen sensor signal
- Throttle position

Read Sensor Values

- Battery temperature
- Coolant temperature
- MAP sensor reading
- Oxygen sensor state
- Throttle opening
- Vehicle speed


ENGINE PARAMETER TEST MODE

The engine parameter test mode shows various positions, voltages, and values associated with engine operation and performance. These values are read from several sensor readings and are used to determine fuel injector pulse width, engine timing, and charging system operation. To enter engine parameter test mode, access "Engine Parameters" on the scan tool.

The following parameters can be monitored in this mode:

- Automatic Idle Speed (AIS) motor position
- Barometric pressure
- Battery voltage
- Engine speed
- Manifold Absolute Pressure (MAP) gauge reading
- Total spark advance