2.
Remove the fuel pump relay.
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.
"Multitester Calibration" of "Details Inspection(Equipment Setting)" reference
Measure the resistance between terminal "85" and terminal "86".
Specification : 95Ω ± 10 % (20℃)
Measure the resistance between terminal "30" and terminal "87".
Specification : Discontinuity (Infinite Ω)
Actuate the relay by suppling battery power and chassis ground at terminal "85", "86".
Specification : Contacts are connected.
Measure the voltage between terminal "30" and terminal "87" when relay is actuated.
Specification : Continuity (below 1.0 Ω)
※ 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.
Case 1 : In case that relay coil resistance is high. (Open)
DTC "P0231 Fuel pump secondary circuit low" is displayed, Engine starting is impossible (Engine stalls) 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 Rail pressure monitoring-Minimum pressure at engine speed too low"
- "P0088 Rail pressure monitoring-Maximum pressure exceeded"
- "P1185 Fuel pressure monitoring-Maximum pressure exceeded"
- "P1186 Fuel pressure monitoring-Minimum pressure at engine speed too low"
Replace the fuel pump relay.
Case 2 : In case that 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.)
DTCs would be displayed as below while driving,
- "P1171 Minimum rail pressure exceeded"
- "P0087 Rail pressure monitoring-Minimum pressure at engine speed too low"
- "P0088 Rail pressure monitoring-Maximum pressure exceeded"
- "P1185 Fuel pressure monitoring-Maximum pressure exceeded"
- "P1186 Fuel pressure monitoring-Minimum pressure at engine speed too low"
Replace the fuel pump relay.
Case 3 : In case that 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 Rail pressure monitoring-Minimum pressure at engine speed too low"
- "P0088 Rail pressure monitoring-Maximum pressure exceeded"
- "P1185 Fuel pressure monitoring-Maximum pressure exceeded"
- "P1186 Fuel pressure monitoring-Minimum pressure at engine speed too low"
Replace the fuel pump relay.
Parts number : 95224 - 29850
Standard : DC 12V 20A (resistance interior relay)
