Scan Tool Testing and Procedures
SCAN TOOL HOOK-UPConnect the scan tool to the [1][2]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 [1][2]diagnostic connector for continuity to ground.
ACCESSING AND DELETING FAULT CODES
CAUTION: Be sure to apply the parking brake and/or block wheels prior to performing any function that requires the engine to be running.
1. Connect the scan tool to the [1][2]diagnostic connector located in the engine compartment near the engine controller.
2. If possible, START the engine and cycle the transmission selector through all of the gears, returning to PARK when finished. If the vehicle has air conditioning, turn the A/C switch ON and then OFF. Turn OFF the ignition switch.
3. Turn the ignition switch ON and observe the CHECK ENGINE LIGHT. It should light for about 3 seconds when the key is turned ON. Access the READ FAULT screen on the scan tool and record any fault messages shown on the screen.
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.
STATE DISPLAY TEST MODE
Inputs and Outputs
The switch inputs read by the engine controller have two recognized states (high and low). Therefore, the engine controller cannot determine the difference between a switch position and an open or shorted circuit, or a defective switch. 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.
Connect the scan tool to the vehicle and access the "State Display" screen. From the "State Display" screen, access the "State Display Inputs and Outputs" screen.
The following components can be monitored in this mode:
- Air conditioning clutch relay
- Air conditioning request input
- Air conditioning select switch
- Auto shutdown relay
- Brake switch
- CHECK ENGINE LAMP
- Cruise lamp
- Cruise power relay
- EGR solenoid
- Fuel flow signal
- J2 voltage sense
- PARK/NEUTRAL switch
- Radiator fan relay
- Speed Control ON/OFF
- Speed control RESUME
- Speed control SET
- Speed control vacuum solenoid
- Speed control vent solenoid
- Vehicle Distance Sensor
- Z2 voltage sense
Sensors
The switch inputs read by the engine controller have two recognized states (high and low). Therefore, the engine controller cannot determine the difference between a switch position and an open or shorted circuit, or a defective switch. 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.
Connect the scan tool to the vehicle and access the "State Display" screen. From the "State Display" screen, access the "State Display Sensors" screen.
The following can be monitored in this mode:
- Adaptive fuel factor
- Automatic Idle Speed (AIS) motor position
- Barometric pressure
- Battery voltage
- Charge temperature
- Charge temperature sensor
- Coolant temperature
- Coolant temperature sensor
- Distributorless Ignition System (DIS) sensor status
- Engine speed
- Fault #1 Key ON Info
- Fault #2 key ON info
- Fault #3 key ON info
- Manifold Absolute Pressure (MAP) gauge reading
- MAP sensor reading
- MAP sensor voltage
- Minimum air flow speed
- Minimum throttle
- Module spark advance
- Oxygen sensor signal
- Oxygen sensor state
- Speed control A2D switch input
- Speed control status
- Speed control target
- Throttle opening
- Throttle position
- Total spark advance
- Vehicle speed
CIRCUIT ACTUATION TEST MODE
The purpose of the circuit actuation test mode is to check for the proper operation of output devices and their respective circuits that the engine controller cannot internally recognize. The engine controller can send an actuation signal to these outputs and allow an observer to check for proper operation. Most of the tests available in this mode provide an audible or visible indication that the device is operating. Except for an intermittent condition, if a device functions properly during it's test, it can be assumed that the device and it's circuit are in working order.
To access the circuit actuation test connect the scan tool to the vehicle and access the "Actuators" screen. The following engine control system functions are accessible through the actuators" screen:
- Air conditioning clutch relay
- Auto shutdown fuel system test
- Auto shutdown relay
- Automatic Idle Speed (AIS) motor open/close
- EGR solenoid
- Fuel flow signal
- Fuel injector #1
- Fuel injector #2
- Fuel injector #3
- Ignition coil #1
- Ignition coil #2
- Ignition coil #3
- Radiator fan relay
- Speed control power relay
- Speed control servo solenoids
- Tachometer output
- All solenoids/relays