Test C: Fuel Tank Temperature Sensor Circuit Failure (DTC B1222)

WARNING: This page is about a different car, the 2002 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition switch to LOCK position. Disconnect NGV module 60-pin harness connector C1009. NGV module is located on left inner fender well, behind coolant recovery bottle. Connect NGV module 60-pin harness connector C1009 and NGV module to 60-pin Breakout Box (014-00322) following manufacturer's instructions. Turn ignition switch to ON position. Measure voltage between breakout box pins No. 46 and 47. If voltage is more than 4.55 volts, go to next step. If voltage is 4.55 volts or less, go to step 5.
Turn ignition switch to LOCK position. Disconnect fuel tank temperature sensor 2-pin harness connector C3124. Fuel tank temperature sensor is located in center fuel tank solenoid valve. See Figure. Connect a fused jumper wire between fuel tank temperature sensor 2-pin harness connector C3124 Gray/Red wire terminal and Orange/Light Green wire terminal. Turn ignition switch to ON position. Measure voltage between breakout box pins No. 46 and 47. If voltage is .12 volt or more, go to next step. If voltage is less than .12 volt, replace fuel tank temperature sensor. See FUEL TANK TEMPERATURE SENSOR under REMOVAL & INSTALLATION. Retest system operation.
Turn ignition switch to LOCK position. Disconnect NGV module from breakout box. Leave NGV module 60-pin harness connector C1009 connected to breakout box. Measure resistance between break out box pin No. 46 and fuel tank temperature sensor 2-pin harness connector C3124 Gray/Red wire terminal. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Gray/Red wire. See WIRING DIAGRAMS . Retest system operation.
Measure voltage between breakout box pin No. 40 or 60 and pin No. 46. If voltage is more than .5 volt, go to next step. If voltage is .5 volt or less, repair short to voltage in Gray/Red wire. See WIRING DIAGRAMS . Retest system operation.
Turn ignition switch to ON position. Measure voltage between breakout box pins No. 46 and 47. If voltage is 4.55 volts or less, go to next step. If voltage is more than 4.55 volts, replace fuel tank temperature sensor. See FUEL TANK TEMPERATURE SENSOR under REMOVAL & INSTALLATION. Retest system operation.
Turn ignition switch to LOCK position. Measure resistance between breakout box pins No. 40 and 46. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Gray/Red wire. See WIRING DIAGRAMS . Retest system operation.

CAUTION: New Generation Star (NGS) tester must be used in this procedure to measure voltage. Using a standard DVOM to carry out this test will cause an inaccurate reading, possibly leading to inaccurate repairs.

Connect NGV module to breakout box. Leave NGV module 60-pin harness connector C1009 connected to breakout box. Connect fuel tank temperature sensor 2-pin harness connector C3124. Connect accessory voltmeter leads to NGS tester. Connect NGS tester positive lead to breakout box pin No. 47. Connect NGS tester negative lead to breakout box pin No. 40 or 60. Turn ignition switch to ON position. Using NGS tester, enter DIGITAL MEASUREMENT SYSTEM. Select VOLTMETER, then LINK. Select PID/DATA, then NGV. Select TEMPS1, then START. Select REC, then press TRIGGER to capture data. Press TRIGGER again to store data, then select VIEW to read data. If voltage varies rapidly between .2-4.9 volts, repair connectors and/or harness for intermittent contact condition. Retest system operation. If voltage does not vary rapidly between .2-4.9 volts, replace NGV module. See NATURAL GAS VEHICLE MODULE under REMOVAL & INSTALLATION. Retest system operation.