Road Test

RECREATING THE SYMPTOM
In order to diagnose driveability problems, the technician must collect data on how the Electronic Engine Control (EEC) system is sensing and reacting.

After a thorough visual and mechanical inspection is completed, the EEC portion is diagnosed. Through the use of a Monitor and a Recorder, these signals can be inspected for shorts, opens, component failures, or erratic behavior.

Also, the data received from the Monitor and Recorder can reveal the presence of mechanical problems.

PREPARATION
1. Place Monitor (and Recorder, optional) in a convenient location inside the vehicle. Secure any cables away from moving engine parts and ignition components.

2. Place the proper overlay card on the monitor. Road Test

3. List the EEC sensors and actuators that could cause the condition. These signals will be monitored during the road test.

4. If a Recorder is used, select the first 8 signals listed to channels 1-8 (one signal per channel). Connect the jumpers from the Input/Output (I/O) jacks to the appropriate channels.

5. Select the proper Diagnostic Reference Value Chart. This chart lists Powertrain Control Module (PCM) sensor and actuator values at various operating conditions.

NOTE: The values given on these sheets are only approximations.

6. In order to safely perform a road test, it is necessary that a second person accompany the driver. The second person can select signals, observe changes, and record notes.

USE OF PERIPHERAL INPUTS
Some useful signals may require the use of certain peripheral (auxiliary) devices. These devices can be inserted into the AUX jacks of the monitor or the ADAPT 1/ADAPT 2 input jacks of the recorder.

REMINDERS
The purpose of the road test is to recreate the driveability problem by duplicating the conditions that caused it. The road test is a suggested but optional part of this section. It is important that the road test be performed safely. Use the provided seat belts and operate the vehicle in a safe manner, obeying all traffic rules and regulations.

OBSERVATIONS
During the road test various PCM signals are chosen and their values shown. Also, the following observations can be made as the road test is performed:

EEC Values -- Compare road test values at various operating conditions with those listed in Diagnostic Reference Values. For more details, Diagnostic Reference Values

Monitor Lights -- Observation of the monitor lights give quick information about the condition of many PCM signals. For example, these lights can quickly reveal the status of many signals, telling the technician whether an output should be energized or not. Optional signals are printed in yellow labels.

Wiggle Tests -- By using the wiggle test mode during Key On Engine Running tests, often an intermittent device or wire will trigger the alarm. The Direct Current Voltage (DCV) wiggle mode in particular is very sensitive to sudden, erratic changes in an EEC-IV harness or component.

ROAD TEST PROCEDURE
1. Using the appropriate routine, select the first listed PCM device on Monitor pin selector "A".

2. Turn ON the monitor (and Recorder, if used). Start and drive the vehicle.

3. If the recorder is installed, put the function switch in RECORD mode and and press the START RECORD button.

4. Drive the vehicle, creating conditions associated with the driveability problem.

5. When the symptom occurs, the passenger should observe changes in the selected PCM signal. Information should be recorded onto paper with other notes about the symptom, device, or operating conditions. If the recorder is used the capture button should be pressed.

6. If the Monitor is used without the Recorder, The next PCM signal on the list can be selected on PIN SELECTOR A. The drive symptom should then be re-created and recorded as in the previous step. This step is to be re-created until the cause of the problem is found or enough data is collected to return and analyze.

7. If the Recorder is used, the accompanying passenger may wish to write down the data from the Recorder channels onto paper. The drive symptom can be created and recorded again for conformation. Otherwise, the road test is completed. To interpret the data received from the road test, refer to Analyzing Data.