Test Procedure

• Connect the diagnostic tool to data link connector (DLC).
• Key in ON position.
• CLEAR the DTCs.

Have the DTCs been cleared? 

• A list of related PIDs and/or signals are needed for use with the diagnostic tool to monitor the suspect areas. Obtain the customer symptom description. Use the Reference Value Symptom chart and proceed to the Reference Value PID/Signal Measurement chart located at the beginning of REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .
• Highlight each available PID/signal recommended by the charts under the PID/signal selection menu on the diagnostic tool.

Have all available PIDs/signals related to the symptom been selected? 

Has a fault symptom been detected? 

• Prepare the freeze frame data for use with information from the SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE .
• CHECK the continuous memory DTCs that should have been recorded from an earlier pinpoint test.
• Access the information from the customer information worksheet and the customer if available. Access any other symptom related data available, such as TSBs and OASIS reports.

Has all available data been recorded? 

• With the diagnostic tool, select and monitor the same PIDs as displayed in freeze frame along with previously selected PIDs/signals from step Z2. Using freeze frame data recorded earlier, recreate the conditions described by each freeze frame PID. Pay special attention to ECT, LOAD, RPM and VSS. Also, use any available data from the customer, TSBs, and other sources to aid in producing the correct conditions for recreating the symptom.
• When the symptom occurs, press the trigger to begin recording. Refer to the diagnostic tool instruction manual for information on the recorder function.

Could the symptom be recreated? 

• The road test is the last attempt to locate the area of concern before physically disturbing vehicle circuits.
  NOTE: PIDs for output in the Reference Value Charts represent command values only. Circuit measurements with a digital multimeter indicate the actual output status. Therefore, in the case of a fault, the PID and circuit reading on the vehicle may not correspond with each other. PIDs for PCM/TCM circuits with a mismatch in the digital multimeter measurement indicate a possible PCM/TCM concern.
• The intermittent road test procedure is a set of instructions for monitoring PIDs/signals with a diagnostic tool and circuit measurements with a digital multimeter. This is done under 4 different conditions - key on/engine off, hot idle, 48 km/h (30 mph) and 88 km/h (55 mph). Use the typical diagnostic Reference Values from REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE to compare with the actual vehicle. For actual road test at speeds, a planned route or test track and passenger is required.
• Locate the correct Reference Value Chart in REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .
• Set the vehicle up to measure the circuits with a digital multimeter and a diagnostic tool.
• Connect the diagnostic tool to data link connector (DLC).
• Key in ON position.
• With the diagnostic tool, select and monitor PIDs and measure circuits shown in the Reference Value Chart in REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .
• Compare the diagnostic tool PIDs and digital multimeter values to the Reference Value Charts.

Are any values out of range? 

• The engine temperature should be at least 87 deg C (195 deg F).
• Key on engine running.
• Continue to monitor the PIDs and circuits as in the previous step.

Are any values out of range? 

• Drive the vehicle on a preplanned route.
• Continue to monitor the PIDs and circuits as in the previous step.

Are any values out of range? 

• Continue to drive the vehicle on the preplanned route.
• Continue to monitor the PIDs and circuits as in the previous step.

Are any values out of range? 

• Remain in the PID/Signal selection menu with the diagnostic tool.
• If the intermittent road test was used to verify the symptom, highlight the PIDs/signals that were displayed as a mismatch to the Reference Values from REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE . Otherwise, highlight only the PIDs/signals from step Z2.
• Proceed to the PCM/TCM PIDS/SIGNALS  chart located at the beginning of this pinpoint test.
• Match the selected PIDs/signals to the corresponding circuit in the chart. There may be more than one circuit to test. If a PID/signal recording was made with the diagnostic tool, it may be helpful to replay it at this time. Refer to the diagnostic tool instruction manual for recorder function information.
  NOTE: From the same chart, be sure to select and proceed with the appropriate test type.
• Input Test - used on sensing inputs such as temperature, position or oxygen.
• Output Test - used on output devices such as relays, coils or solenoids.

Has a test been chosen? 

• Using the circuits chosen from the PCM/TCM PIDS/SIGNALS  Chart, select only the recommended PIDs/signals to monitor with the diagnostic tool. If a PID is not available for the circuit, use a digital multimeter to check the value.
• Proceed to the area of the suspect wiring or component fault.
• Key in ON position.
• If the input is a switch type-component, turn it on manually.
• Monitor the PID or digital multimeter while tapping on the component.
• Monitor while wiggling the sensor harness wire from the component to the PCM/TCM.
• Look for abrupt changes in the values. Compare these actual values to the Typical Diagnostic Reference Values in REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .

Are there abrupt changes in the PID values that do not compare with  REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE  readings? 

• Key on engine running.
• Continue to monitor the PIDs and circuits as in the previous step.
• Proceed to the area of the suspect wiring or component fault.
• If the input is a switch type-component, turn it on manually.
• Monitor the PID or digital multimeter while tapping on the component.
• Monitor while wiggling the sensor harness wire from the component to the PCM/TCM.
• Look for abrupt changes in the values. Compare these actual values to the Typical Diagnostic Reference Values in REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .

Are any values fluctuating in and out of range? 

• Key in ON position.
• Continue to monitor the PIDs and circuits as in the previous step.
• Proceed to the area of the suspect wiring or component fault.
• If the input is a switch type-component, turn it on manually.
• Monitor the PID or digital multimeter values while lightly spraying a water mist on the component to PCM/TCM.
• Monitor while spraying the sensor harness wire from the component to the PCM/TCM.
• Look for abrupt changes in the values. Compare these actual values to the Typical Diagnostic Reference Values in REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .

Are any values fluctuating in and out of range? 

• Key on engine running.
• Continue to monitor the PIDs and circuits as in the previous step.
• Proceed to the area of the suspect wiring or component fault.
• If the input is a switch type-component, turn it on manually.
• Monitor the PID or digital multimeter values while lightly spraying a water mist on the component to PCM/TCM.
• Monitor while spraying the sensor harness wire from the component to the PCM/TCM.
• Look for abrupt changes in the values. Compare these actual values to the Typical Diagnostic Reference Values in REFERENCE VALUES - CNG, FLEX-FUEL & GASOLINE .

Are any values fluctuating in and out of range? 

• Using the circuits chosen from the PCM/TCM PIDS/SIGNALS  Chart, select only the recommended PIDs/signals to monitor with the diagnostic tool. If a PID is not available for the circuit, use a digital multimeter to check the value.
  NOTE: Remember that PIDs selected from the Intermittent Test Chart display commanded values only. A digital multimeter measurement is needed to display the actual values. Be sure to compare them. Look for fluctuations to occur during any part of the following test. The Output State Test may not control some outputs, such as injectors and ignition coils and may not be available for all actuators.