4.
Measure the resistance between terminal "85" and terminal "86".
■ Specification : 85Ω ± 10 % (20℃)
First of all check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
When battery power is not supplied to low pressure fuel pump although fuel pump relay circuit is normal, Inspect the fuel pump relay.
IG KEY "OFF", ENGINE "OFF"
Remove the fuel pump relay.
Before measuring resistance, you must calibrate(0Ω) the tester.
Refer to "Multimeter calibration" of detail inspections (Equipment settings).
Measure the resistance between terminal "85" and terminal "86".
■ Specification : 85Ω ± 10 % (20℃)
Measure the resistance between terminal "30" and terminal "87".
■ Specification : Discontinuity (Infinite Ω)
Actuate the relay by supplying battery power and chassis ground at terminal "85", "86".
☞ Inspect operating sound in the main relay when power is supplied.
Measure the resistance between rely component terminal "30" and "87".
■ Specification : Continuity (below 1.0Ω)
※ If trouble symptom occurs intermittently although relay is operated well as above, Inspect the inside of the relay.
☞ Make sure of damage of the relay cover.
- Contact : Inspect contact connection and carbon deposit by spark.
- Coil : Inspect partial damage by coil short and enamel coating damage.
Symptom | Inspection procedure | |
Case1 | ● Relay coil resistance is high. (Open) | ● "P0231 Fuel pump secondary circuit Low" is displayed, Engine starting is impossible (Engine stalls) because battery power is not supplied to fuel pump at IG KEY "ON. ● DTCs would be displayed as below while driving, ☞ "P1171 Minimum rail pressure exceeded", ☞ "P0087 Fuel rail/system pressure - Too Low", ☞ "P0088 Fuel Rail/System Pressure - Too High", ☞ "P1185 Maximum Pressure Exceeded", ☞ "P1186 Minimum Pressure at Engine Speed Too Low" ● Replace the fuel pump relay. |
Case2 | ● Relay coil resistance is low. (Short) | ● DTC "P0232 Fuel pump secondary circuit high" is displayed, Engine starting is impossible (Engine stalls) because of battery power is not supplied to fuel pump at IG KEY "ON. ● ECM can be damaged. (According to short condition over current is supplied to relay control circuit in the ECM.) ☞ "P1171 Minimum rail pressure exceeded", ☞ "P0087 Fuel rail/system pressure - Too Low", ☞ "P0088 Fuel Rail/System Pressure - Too High", ☞ "P1185 Maximum Pressure Exceeded", ☞ "P1186 Minimum Pressure at Engine Speed Too Low" ● Replace the fuel pump relay. |
Case3 | ● Relay coil is normal. (Intermittent poor contact connection) | ● Engine starting is impossible (Engine stalls) intermittently because of battery power is not supplied to fuel pump at IG KEY "ON. ● DTCs would be displayed as below while driving, ☞ "P1171 Minimum rail pressure exceeded", ☞ "P0087 Fuel rail/system pressure - Too Low", ☞ "P0088 Fuel Rail/System Pressure - Too High", ☞ "P1185 Maximum Pressure Exceeded", ☞ "P1186 Minimum Pressure at Engine Speed Too Low" ● Replace the fuel pump relay. |
