Methods Of EEC-IV Monitor Measurements

Here are ten basic methods to measure and diagnose EEC signals. Other less common methods are detailed in the monitor manuals.

CHANGE CONDITION TO CAUSE RESPONSE BY INPUT
Purpose: Verify sensor receives and responds to changes.
1. KOEO or KOER; AUTO or DCV mode.
2. Select sensor on PIN SELECTOR A.
3. Create condition or change in condition.
4. Observe change in sensor value; verify with EEC Graphs and Charts. Graphs and Charts - Sensor Values
5. Examples:
Move throttle, observe TP increase, MAP increase.
Warm-up engine, observe IAT, ECT decrease.
Press brake pedal, observe BOO light.

CHANGE INPUT AND VERIFY OUTPUT RESPONSE
Purpose: Verify EEC module and actuator circuit responds to sensor input.
1. KOEO or KOER; AUTO or DCV mode.
2. Select actuator on PIN SELECTOR A or B.
3. Create change for input device with switch box or vehicle operation.
4. Observe change (response) in actuator signal, observe light.
5. Examples:
Increase throttle (TP), observe SPOUT increase.
Move EGO switch to LEAN, observe SPOUT increase.

CHECK VALUE
Purpose: Verify correct value for device/signal.
1. KOEO/KOER; AUTO or DCV mode.
2. Select signal from PIN SELECTOR A or B.
3. Various units used, refer to meter function light.

CLICK-TESTING (RELAYS/SOLENOIDS)
Purpose: Activate solenoid or relay from EEC monitor and observe device.
1. KOEO only; AUTO or DCV mode.
2. Select relay or solenoid signal on PIN SELECTOR A and correct ground on REFERENCE PIN selector.
3. Insert switch box into SELECTOR PIN jacks.
4. Push small red button to turn ON relay or solenoid.
5. Listen for "click" of device turning ON, observe monitor box LED signal light turning on.

COIL RESISTANCE (SOLENOIDS/RELAYS)
Purpose: Measure for correct resistance value of device.
1. Key OFF only; Ohms mode.
2. Select signal from PIN SELECTOR A.
3. Select correct ground from REFERENCE PIN SELECTOR.
4. Select OHMS RANGE switch.
5. WIGGLE TEST will light and sound; press WIGGLE TEST RESET button.
6. Manual test light should be blinking; value in ohms units.

EEC INPUT CHECK
Purpose: Confirm that PCM sets the malfunction indicator lamp for certain sensors.
1. KOEO; DCV mode.
2. Select sensor from PIN SELECTOR A.
3. Set REFERENCE PIN SELECTOR to SIG RTN.
4. Insert switch box into SELECTOR PIN jacks.
5. Move AIM switch to KEY ON, ENGINE OFF position.
6. Push small red button on switch box and observe STO light turning on and beeper sounding as long as button is pressed.
7. Return AIM switch to OFF position.

HARNESS OPENS
Purpose: Check harness for open circuits.
1. Key OFF; Ohms mode.
2. Select signal from PIN SELECTOR A.
3. Disconnect sensor/actuator where signal is to be checked.
4. Connect jumper wire from REFERENCE PIN jack (black) to signal pin on harness to be tested.
5. Check for continuity -- 0 ohms = OK.

HARNESS SHORTS
Purpose: Check harness for short circuits (to ground or power).
1. Key OFF; Ohms mode.
2. Select signal from PIN SELECTOR A.
3. Set OHMS RANGE switch to 200K.
4. Disconnect sensor/actuator to be tested.
5. Optional: Disconnect EEC (reconnect monitor to EEC harness).
6. Select various power or ground signals from REFERENCE PIN SELECTOR. Example: VREF, SIG RTN, PWR GND.
7. Read resistance: 0 or low ohms indicates a short, 10K or higher ohms -- no short.

OUTPUT STATE CHECK (SOLENOIDS/RELAYS)
Purpose: Exercise actuator devices after KOEO DTM.
1. KOEO; AUTO or DCV mode.
2. Move AIM switch to KEY ON ENGINE ON position and wait for output codes (beeps) to end.
3. Completely depress and release throttle -- observe monitor LED signal light turning ON.
4. Completely depress and release throttle -- monitor LED light should turn OFF.
5. Return AIM switch to OFF position.

WIGGLE TESTING (DCV OR OHMS)
Purpose: Sensitive DCV or ohms testing for intermittent harness or device.
1. Key OFF only for OHMS wiggle; KOEO or KOER for DCV wiggle.
2. Use DCV wiggle for all actuators, power and ground signals, and all sensors which use DCV units in AUTO mode; all others use OHMS wiggle.
3. Example: Ohms wiggle MAP, PIP, INJ(S); DCV wiggle - TP, ECT, EVR. DCV wiggle is more sensitive than the ohms wiggle test.
4. Select signal from PIN SELECTOR A.
5. Select correct ground from REFERENCE PIN SELECTOR.
6. Tap components, flex harness and connectors.
7. Wiggle test light and beeper will activate when change sensed.