LEMON Manuals: Even more car manuals for everyone
Home >> Cadillac >> 1997 >> Catera >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Symptom Testing >> Fuel Gauge Inaccurate Or Inoperative

Fuel Gauge Inaccurate Or Inoperative

  1. Perform INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  under TROUBLE SHOOTING. Go to next step.
  2. If fuel gauge is inoperative, go to next step. If fuel gauge works, go to step 4).
  3. Install scan tool to DLC. See COMPONENT LOCATIONS  . Select SPECIAL FUNCTIONS from the INSTRUMENT PANEL CLUSTER MENU. Command fuel gauge from empty to full and back. If gauge responds as specified, go to step 5). If gauge does not respond as specified, go to step 6).
  4. If fuel gauge is inaccurate, go to step 7). If fuel gauge is accurate, test is complete.
  5. Disconnect C400 connector. C400 is located under car near front of fuel tank. See Figure . Turn ignition switch to ON position. Use DVOM and measure voltage between ground and C400 terminal "C" (Blue/Black wire). If battery voltage is indicated, go to step 8). If battery voltage is not indicated, go to step 9).
  6. Replace and program the instrument cluster. See procedures in INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Go to INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  .
  7. Install scan tool to DLC. See COMPONENT LOCATIONS  . Select FUEL LEVEL GAUGE and ACTUAL FUEL LEVEL from data list. Wait for a minimum of 5 minutes for readings to stabilize. If both readings are approximately the same, go to INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  . If readings are different, go to step 10).
  8. Turn ignition switch to OFF position. Use DVOM and measure resistance between ground and C400 terminal "B" (Black wire). If reading is 5 ohms or less, go to step 6). If reading is greater than 5 ohms, go to step 11).
  9. Locate and repair open in Blue/Black wire between connector C400 terminal "C" and instrument cluster terminal No. 20. See WIRING DIAGRAMS  . If circuit was repaired, see procedures in INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  . If circuit is okay, go to step 6).
  10. Connect a signal generator tool, an appropriate resistor or a potentiometer between C400 terminal "C" (Blue/Black wire) and ground. Ignition switch will need to be cycled off and on when a new resistance is value is used. Compare readings on scan tool and gauge with values in FUEL GAUGE VALUES  table. If values are approximately the same, go to step 12). If values are not even close, go to step 6).
  11. Locate and repair excessive resistance in ground circuit for sending unit. After repair, go to INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  .
  12. Replace fuel sending unit. See FUEL TANK SENSOR/FUEL PUMP  under REMOVAL & INSTALLATION. Go to INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  .
FUEL GAUGE VALUES

Actual Gauge Reading Ohms Value Used Scan Tool Display (Volts) Scan Tool Display (Gallons)
Full 42.7 (1) 1.7 18
3/4 82 (1) 3 12.5
1/2 116.5 (1) 3.9 9
1/4 176.8 (1) 5.1 4.5
Empty 272.4 (1) 6.2 0
(1) Approximate resistance value.
scientia non olet · About LEMON Manuals