P0230

1GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0230: Fuel Pump Primary Circuit

DTC P0230 - Fuel Pump Primary Circuit

DESCRIPTION

As shown in the illustration, when the engine is cranked, current flows from terminal ST1 of the ignition switch into the ECM and the ST (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, 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 engine condition (starting, light load, heavy load). When the engine starts (STA ON), Tr2 (power transistor 2) in the ECM is OFF, so the fuel pump relay closes and positive battery voltage is applied directly to the fuel pump. The fuel pump operates at high speed.
During idling or under light loads, Tr2 goes ON, and then power is supplied to the fuel pump via the fuel pump resistor. The fuel pump operates at low speed.









WIRING DIAGRAM




HINT: This DTC chart is on the premise that the engine is started normally. If the engine is difficult to start, proceed to the problem symptoms table Symptom Related Diagnostic Procedures.

INSPECTION PROCEDURE
HINT: Read freeze frame data using the Techstream. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

PROCEDURE

1. INSPECT ECM (FPR VOLTAGE)




(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:






NG -- REPLACE ECM
OK -- Continue to next step.

2. INSPECT FUEL PUMP RELAY ASSEMBLY




(a) Remove the fuel pump relay from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(c) Reinstall the fuel pump relay.
NG -- REPLACE FUEL PUMP RELAY ASSEMBLY
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (F/PMP RELAY - ECM)




(a) Remove the fuel pump relay from the engine room relay block.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):






Standard Resistance (Check for Short):





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