Civic L4-1.7L CNG (2003)
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away
with a known-good PCM, replace the original PCM.
76. Watch the low fuel indicator light. Does the low fuel indicator light blink?
YES - Check the low fuel indicator light
NO - Go to step 77.
77. Turn the ignition switch OFF.
78. Turn the ignition switch ON (II).
79. Measure voltage between PCM connector terminal E29 and body ground.
Is there about 5 V (or battery voltage)?
YES - Go to step 83.
NO - Go to step 80.
80. Turn the ignition switch OFF.
81. Disconnect PCM connector E (31P).
82. Check for continuity between PCM connector terminal E29 and body ground.
Is there continuity?
YES - Repair short in the wire between the DLC and the PCM (E29).
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away
with a known-good PCM, replace the original PCM.
83. Turn the ignition switch OFF.
84. Disconnect PCM connector E (31P).
85. Turn the ignition switch ON (II).
Does MIL stay on?
YES - Repair short in the wire between the gauge assembly and the PCM (E31). If the wires are OK, replace the gauge assembly.
