P0230

2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0230: Fuel Pump Primary Circuit

DTC P0230 - Fuel Pump Primary Circuit

DESCRIPTION

In the diagram below, when the engine is cranked, current flows from terminal STAR NSW of the ECM to the starter relay coil and also current flows to terminal STA of the ECM (STA signal).
When the STA signal and NE signal are input to the ECM, the Tr1 (power transistor 1) is turned ON, current flows to the coil of the circuit opening relay, the relay switches on, power is supplied to the fuel pump, and the fuel pump operates.
While the NE signal is generated (engine running), the ECM keeps the Tr1 ON (circuit opening relay ON) and the fuel pump also keeps operating.
The fuel pump speed is controlled at two levels (high speed or low speed) by the engine condition (starting, light load, heavy load). When the engine starts (STA ON), the Tr2 (power transistor 2) in the ECM is OFF, so the fuel pump relay closes and battery positive voltage is applied directly to the fuel pump. The fuel pump operates at high speed.
After the engine starts during idling or light loads, since the Tr2 goes ON, power is supplied to the fuel pump via the fuel pump resistor. The fuel pump operates at low speed.









WIRING DIAGRAM




HINT: This troubleshooting procedure is based on the premise that the engine is started. If the engine is not started, proceed to the problem symptoms table Symptom Related Diagnostic Procedures.

INSPECTION PROCEDURE
HINT: Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. CHECK ECM (FPR VOLTAGE)




(a) Measure the voltage of the ECM connector.
Standard voltage:






OK -- REPLACE ECM
NG -- Continue to next step.
2. INSPECT FUEL PMP RELAY ASSEMBLY




(a) Remove the FUEL PMP relay from the engine room R/B.
(b) Measure the resistance of the FUEL PMP relay.
Standard resistance:





(c) Reinstall the FUEL PMP relay.
NG -- REPLACE FUEL PMP RELAY ASSEMBLY
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (FUEL PMP RELAY - ECM)




(a) Remove the FUEL PMP relay from the engine room R/B.
(b) Disconnect the E7 ECM connector.
(c) Measure the resistance between wire harness side connectors.
Standard resistance (Check for open):






Standard resistance (Check for short):





(d) Reconnect the ECM connector.
(e) Reinstall the FUEL PMP relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM