SYS.OK|MANUAL.DBâ—Ź LIVE
HOMESERVICE MANUALSMERCURY1991TRACER BASE, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - SYSTEM/COMPONENT TESTS - 1.9LEDIS SYSTEMPINPOINT TEST B
1991 Mercury Tracer Base, 4D Sedan, Automatic

Pinpoint Test B

1991 Mercury Tracer Base, 4D Sedan, AutomaticSECTION Pinpoint Test B
  1. Check For IDM Signal At EDIS Module  With key off, connect EDIS diagnostic cable to BOB, EDIS module, and coil pack. Do not connect VR sensor tee. Use EDIS "4" overlay. Connect EDIS diagnostic cable negative and positive leads to battery. Set EDIS diagnostic cable box switch to "4/6 cylinder" position. Set DVOM on 20-volt AC scale. Start engine and measure voltage between diagnostic cable IDM DETECTOR (30) and BAT- (7) at BOB. If the AC voltage is greater than 0.5 volt, go to step 2. If voltage is 0.5 volt or less, go to step 3.
  2. Check For IDM Open  With key off, disconnect ECA. Disconnect EDIS module from EDIS module tee, leave EDIS diagnostic cable connected to vehicle harness connector. Connect ECA BOB to ECA harness connector. Set DVOM on 200-ohm scale. Measure resistance between IDM E (41) at BOB, and terminal No. 4 at ECA BOB. If resistance is 5 ohms or less, replace ECA. IDM signal at ECA is okay. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If resistance is greater than 5 ohms, repair short circuit. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test.
  3. Check IDM Output From EDIS Module, Isolate Harness  With key off, ensure ECA is connected. Set DVOM on 20-volt AC scale. Start engine and push EDIS IDM button at the EDIS diagnostic cable connector to BOB. Measure voltage between diagnostic cable IDM DETECTOR (30) and BAT- (7) at BOB. If AC voltage is greater than 0.3 volt, go to step 4. If voltage is 0.3 volt or less, replace EDIS module. No IDM output from module. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test.
  4. Check For IDM Short In ECA, Isolate ECA  With key off, disconnect ECA. Set DVOM on 20-volt AC scale. Crank engine and measure voltage between diagnostic cable IDM DETECTOR (30) and BAT- (7) at BOB. If AC voltage is greater than 0.3 volt, replace ECA. IDM circuit is shorted in ECA. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If voltage is 0.3 volt or less, go to step 5.
  5. Check For IDM Short To Ground In Harness  With key off, disconnect ECA. Disconnect EDIS module from diagnostic cable module tee, leave EDIS diagnostic cable connected to vehicle harness connector. Set DVOM on 20-volt DC scale. Measure voltage between IDM E (41) and BAT- (7) at BOB. If DC voltage is greater than 0.5 volt, repair short circuit. IDM is shorted to VBAT. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If voltage is 0.5 volt or less, go to step 6.
  6. Check For IDM Short To VBAT In Harness  With key off disconnect ECA. Set DVOM on 20-volt DC scale. With KOEO, measure voltage between IDM E (41) and BAT- (7) at BOB. If DC voltage is greater than 0.5 volt, repair short circuit. IDM is shorted to VBAT between EDIS module and ECA. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If voltage is not as specified, repair short circuit or replace harness IDM is shorted to another wire between EDIS module and ECA. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test.
CAUTION: Never connect ECA to ECA BOB when performing EDIS diagnostics unless directed to do so.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.