Diagnostic Aids

If any sensor using a 5-volt bias voltage, such as the intake air temperature (IAT) sensor or fuel level sensor, is shorted to voltage, DTC P0651 may set in addition to DTC P0641.
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC P0641

Step	Action	Values	Yes	No
Schematic Reference: Instrument Cluster Schematics in Instrument Panel, Gages, and Console or Engine Controls Schematics Connector End View Reference: Instrument Panel, Gages, and Console Component Views , Instrument Panel, Gages, and Console Connector End Views in Instrument Panel, Gages, and Console, or Powertrain Control Module (PCM) Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition cycle?	-	Go to Step 3	Go to Diagnostic Aids
3	Turn OFF the ignition. Disconnect the exhaust gas recirculation (EGR) valve. Turn ON the ignition, with the engine OFF. Command the EGR solenoid to 100 percent with a scan tool. Measure the voltage from the 5-volt reference circuit to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range?	4.8-5.2 V	Go to Step 5	Go to Step 4
4	Is the voltage measured in the previous step more than the specified value?	5.2 V	Go to Step 8	Go to Step 6
5	Connect the EGR valve. Disconnect the manifold absolute pressure (MAP) sensor. Command the EGR solenoid to 100 percent with a scan tool. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range?	5.2 V	Go to Intermittent Conditions	Go to Step 11
6	Monitor a DMM while disconnecting all other devices connected to the 5-volt reference circuit, one at a time. If voltage changes when one of the devices are disconnected, replace the component. Refer to the appropriate replacement procedure below: The MAP sensor-Refer to Manifold Absolute Pressure (MAP) Sensor Replacement . The fuel tank pressure (FTP) sensor-Refer to Fuel Tank Pressure Sensor Replacement . Was a component replaced?	-	Go to Step 13	Go to Step 7
7	Test the 5-volt reference circuit for a short to ground or any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 12
8	Monitor the DMM while disconnecting the MAP sensor, the FTP sensor, and the fuel level sensor, one at a time. Refer to Engine Controls Connector End Views . If the voltage returns to within the specified value when one of the devices is disconnected, test that sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	4.8-5.2 V	Go to Step 13	Go to Step 9
9	Test the 5-volt reference circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 10
10	Test for a short between the EGR 5-volt reference circuit and the EGR solenoid high control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 12
11	Replace the EGR valve. Refer to Exhaust Gas Recirculation (EGR) Valve Replacement . Did you complete the replacement?	-	Go to Step 13	-
12	Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?	-	Go to Step 13	-
13	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 14
14	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?		Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK