1991 Acura Legend code 43

Tiny
RALLIFORDLEGEND
  • MEMBER
  • 1991 ACURA LEGEND
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
Showing engine code 43 in 1991 acura legend. I know this is for the left fuel supply system but what is the left fuel supply system?
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Thursday, June 16th, 2011 AT 3:21 AM

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Tiny
KHLOW2008
  • EXPERT
Most likely a failed O2 sensor.

Here are the description of the code and diagnostices procedures.

CODE 43, CODE 44: FUEL SUPPLY SYSTEM

1. Turn ignition off. Remove ACG fuse in underdash fuse box for 10 seconds to reset ECU. Start engine, and allow cooling fan to come on. Hold engine at 3000 RPM for 2 minutes. Connect jumper wire to diagnostic connector. Observe CHECK ENGINE light. If light does not flash, problem is intermittent.

2. Check for poor or loose connections at left O2 sensor (Code 43) or right O2 sensor (Code 44), ECU and connectors C355, C354 and C356 at right shock tower.

3. If CHECK ENGINE light is flashing Code 43 and/or 44, turn ignition off. If driveability problems are also present, test fuel related components. Repair as necessary.

4. Disconnect ECU connector. Connect ECU test harness between harness
connector and ECU. Turn ignition off, and wait at least 2 minutes.

5. If Code 43 is present, install a jumper wire between terminals A10 and A26. Attach a digital voltmeter to terminal D14. Turn ignition on. Voltage should be.4-.5 volt, and then drop to below.1 volt within 2 minutes.

6. If O2 sensor does not respond as described, go to next step. If voltage changes as described, substitute a known good ECU, and retest system. If problem goes away, replace ECU.

7. Ensure White wire between ECU terminal D14 and O2 sensor terminal "B" has good continuity. If wire is okay, replace O2 sensor.

8. If Code 44 is present, install a jumper wire between terminals A12 and A26. Attach a digital voltmeter to terminal D16. Turn ignition on. Voltage should be.4-.5 volt, and then drop to below.1 volt within 2 minutes.

9. If O2 sensor does not respond as described, go to next step. If voltage changes as described, substitute a known good ECU, and retest system. If problem goes away, replace ECU.

10. Ensure Red/Blue wire between ECU terminal D16 and O[I2] sensor terminal "B" has good continuity. If wire is okay, replace O2 sensor.
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Thursday, June 16th, 2011 AT 12:28 PM

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