Test TC-23A - Flex Fuel Sensor Volts Too High/Low (DTC 64)

WARNING: This page is about a different car, the 1994 Eagle Vision, 1994 Dodge Intrepid, 1994 Chrysler New Yorker, 1994 Chrysler LHS, and 1994 Chrysler Concorde. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For circuit & connector terminal identification, see CONNECTOR IDENTIFICATION DIRECTORY TABLE . For wiring diagrams, see WIRING DIAGRAMS section. After each repair, perform TEST VER-2 .

Using DRB, read flex fuel sensor voltage. If voltage is more than 4.5 volts, go to step 6). If voltage is less than 4.5 volts, go to next step.
If voltage is less than 0.2 volt, go to step 9). If voltage is more than 0.2 volt, wiggle flex fuel sensor connector and harness while observing DRB display. Flex fuel sensor is located in trunk behind trunk liner on rear passenger seat lower crossmember. If flex fuel sensor voltage changes when flex fuel sensor connector and harness are wiggled, repair harness or connector that caused the voltage change. If flex fuel sensor voltage does not change when flex fuel sensor connector and harness are wiggled, go to next step.
At this time, the condition required to set the trouble code is not present. FLEX FUEL SENSOR VOLTS TOO HIGH trouble code sets if flex fuel sensor output voltage is more than 4.5 volts. Possible causes are: flex fuel sensor signal wire open, flex fuel sensor failure, flex fuel sensor ground circuit open. Go to next step.
FLEX FUEL SENSOR VOLTS TOO LOW trouble code sets if flex fuel sensor signal output voltage is less than 0.5 volt. Possible causes are: flex fuel sensor short to ground, flex fuel sensor failure, or powertrain control module failure. Go to next step.
Inspect flex fuel sensor wiring and connectors. Repair as required. If wiring and connectors are okay, see INACTIVE TROUBLE CODE CONDITION in this article. Test is complete.
If voltage is more than 4.5 volts in step 1), disconnect flex fuel sensor connector. Connect a jumper wire between flex fuel sensor connector terminals No. 1 (Yellow/White wire) and No. 2 (Black/Light Blue wire). Using DRB, read flex fuel sensor voltage. If voltage is less than one volt, replace flex fuel sensor. If voltage is more than one volt, move jumper wire from flex fuel sensor connector terminal No. 2 (Black/Light Blue wire) to chassis ground. Go to next step.
Using DRB, read flex fuel sensor voltage. If voltage is less than one volt, repair open Black/Light Blue wire. If voltage is more than one volt, go to next step.
Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. PCM is located under air cleaner. Using DRB in ohmmeter mode, check resistance of flex fuel sensor connector terminal No. 1 (Yellow/White wire). If resistance is less than 5 ohms, replace PCM. If resistance is more than 5 ohms, repair open Yellow/White wire.
Disconnect flex fuel sensor connector. Flex fuel sensor is located in trunk behind trunk liner on rear passenger seat lower crossmember. Using DRB, read flex fuel sensor voltage. If voltage is more than one volt, replace flex fuel sensor. If voltage is less than one volt, go to next step.
Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. PCM is located under air cleaner. Using an external ohmmeter, check resistance between flex fuel sensor connector terminals No. 1 (Yellow/White wire) and No. 2 (Black/Light Blue wire). If resistance is less than 5 ohms, repair Yellow/White wire shorted to Black/Light Blue wire. If resistance is more than 5 ohms, go to next step.
Using DRB in ohmmeter mode, check resistance of flex fuel sensor connector terminal No. 1 (Yellow/White wire). If resistance is more than 5 ohms, replace PCM. If resistance is less than 5 ohms, repair short to ground in Yellow/White wire.