Generator Fr Signal Circuit: Civic
- Turn ignition off. Disconnect 4-pin generator connector. Turn ignition on. Backprobing, measure voltage between PCM connector "A" (31-pin connector) terminal No. 24 (Brown/Yellow wire) and PCM connector "B" (24-pin connector) terminal No. 13 (White/Red wire). See Figure and Fig 1
. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 4.
- Turn ignition off, and reconnect generator 4-pin connector. Start engine. Hold engine speed at 3000 RPM under no load with transaxle in Neutral or Park until radiator cooling fan comes on. Allow engine to idle. Backprobing, measure voltage between PCM connector "A" (31-pin connector) terminal No. 24 (Brown/Yellow wire) and PCM connector "B" (24-pin connector) terminal No. 13 (White/Red wire) while turning headlights and rear window defogger on. See Figure and Fig 1
. If voltage does not decrease when headlights and rear window defogger are turned on, go to next step. If voltage does decrease when headlights and rear window defogger are turned on, problem is intermittent. Generator FR signal is okay at this time.
- Turn ignition off. Disconnect negative battery cable. Disconnect PCM connector "B" (24-pin connector) and 4-pin generator connector. Using a jumper wire, connect White/Red wire of 4-pin generator connector terminal No. 4 to body ground. See Figure. Measure continuity of White/Red wire between body ground and PCM connector "B" (24-pin connector) terminal No. 13. See Fig 1. If continuity is present, test charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If continuity is not present, repair open in White/Red wire between generator and PCM connectors. See WIRING DIAGRAMS article.
- Turn ignition off. Disconnect negative battery cable and PCM connector "B" (24-pin connector). Measure continuity of White/Red wire between body ground and PCM connector "B" (24-pin connector) terminal No. 13. See Fig 1. If continuity is present, repair short in White/Red wire between generator and PCM connectors. See WIRING DIAGRAMS article. If continuity is not present, update PCM if latest software is not installed or substitute known-good PCM and retest. See POWERTRAIN CONTROL MODULE RESET PROCEDURE and SUBSTITUTING POWERTRAIN CONTROL MODULE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - CIVIC (EXCEPT GX & HX MODELS) article. If symptom/indication goes away, replace original PCM.
Courtesy of AMERICAN HONDA MOTOR CO., INC.