DTC P0641
- With the ignition OFF, disconnect the harness connector at the MAP sensor.
- With the ignition ON, measure for 4.8-5.2 volts between the FTP sensor 5-volt reference circuit and ground.
- Command the EGR valve to 100 percent while monitoring the FTP sensor 5-volt reference circuit with a DMM.
- With the ignition OFF, disconnect the harness connector at the EGR valve.
- With the ignition ON, measure EGR valve 5-volt reference circuit.
- If within 4.8-5.2 volts, replace the EGR valve.
- If over 5.2 volts, check for unexpected voltage at each 5-volt reference circuit or the signal circuit for each component associated with the 5-volt reference.
- If under 4.8 volts, check for a short to ground or low reference circuit at each 5-volt reference circuit.
- With the ignition ON, use a scan tool to observe the voltage parameter for each component associated with the 5-volt reference circuit while disconnecting each component one at a time.
- If the data parameters change with any component being disconnected, replace the component.
- If all circuits tested are OK, replace the control module.