general information - Martin Nez

FI SYSTEM DIAGNOSIS 4-7Continuity check• Measure resistance across coupler B (between A and C inthe figure).If no continuity is indicated (infinity or over limit), the circuit isopen between terminals A and C.1 ECM• Disconnect the coupler B and measure resistance betweencouplers A and B.If no continuity is indicated, the circuit is open between couplersA and B. If continuity is indicated, there is an open circuitbetween couplers B’ and C or an abnormality in couplerB’ or coupler C.1 ECMVOLTAGE CHECKIf voltage is supplied to the circuit being checked, voltage checkcan be used as circuit check.• With all connectors/couplers connected and voltage appliedto the circuit being checked, measure voltage between eachterminal and body ground.If measurements were taken as shown in the figure at the rightand results are as listed below, it means that the circuit is openbetween terminals A and B.Voltage Between:C and body ground: Approx. 5 VB and body ground: Approx. 5 VA and body ground: 0 VAlso, if measured values are as listed below, a resistance(abnormality) exists which causes the voltage drop in the circuitbetween terminals A and B.Voltage Between:C and body ground: Approx. 5 VB and body ground: Approx. 5 V 2 V voltage dropA and body ground: 3 V0 V5 V5 V5 V