Honda >> Honda 84-85 Accord & 87 Civic

General Information

  • Trouble codes are displayed by four LED’s in engine control module (ECM) 1
  • LED’s are numbered 8-4-2-1, left to right

Accessing Trouble Codes

  • Access engine control module (ECM):
  • Civic 2
  • Accord¬†3
  • Switch ignition ON
  • Check MIL illuminates
  • Check LED’s in ECM are flashing
  • Count LED flashes and compare with trouble code table below
  • If malfunction indicator lamp (MIL) is ON constantly and no trouble codes are displayed (LED not flashing), this indicates an engine control module (ECM) fault
  • Switch ignition OFF

Clearing Trouble Codes

  • After the faults have been rectified, erase the trouble codes as follows:
  • Civic – Remove fuse No. 10 (10A) from LH fascia fusebox for 10 seconds minimum
  • Accord – Disconnect battery ground cable for 10 seconds minimum
  • Reinstall fuse
  • Repeat accessing procedure to ensure no data remains in ECM fault memory

 Trouble Codes

84-85 Accord 1.8L Engine Code: ES3
87 Civic 1.5L Engine Code: D15A3
Trouble code Fault location Probable Cause
0000 MIL only illuminated -ECM or ECM wiring fault Wiring, ECM
0001 Oxygen sensor (02S) Spark plug misfire, wiring, 02S, ECM
0020 Engine control module (ECM) ECM
0021 Manifold absolute pressure (MAP) sen sor Wiring, MAP sensor, ECM
0400 Engine control module (ECM) -ECM
0401 Manifold absolute pressure (MAP) sensor vacuum hose Hose leak
0420 Engine coolant temperature (ECT) sen sor Wiring, ECT sensor, ECM
0421 Throttle position (TP) sensor Wiring, TP sensor, ECM
8000 Engine speed (RPM)/crankshaft position (CKP) sensors Wiring, RPM/CKP sensor, ECM
8001 Engine speed (RPM)/camshaft position (CMP) sensors RPMICMP sensor, ECM
8020 lntake air temperature (lAT) sensor Wiring, IAT sensor, ECM
8021 CO adjustment resistor Wiring, CO adjustment resistor, ECM
8400 Engine control module -Civic ECM
8400 Exhaust gas recirculation (EGR) control system -Accord Hose leak/blockage, wiring, EGR valve/position sensor, EGR solenoid, ECM
8401 Barometric pressure sensor (BARO) Wiring, BARO sensor, ECM
8420 Engine control module (ECM) ECM
8421 Engine control module (ECM) ECM