HITACHI Construction 4JJ1 P0092 Fuel Pressure Regulator Control Circuit High

Here car-auto-repair.com show you guide on how to solve ISUZU construction 4JJ1 engine P0092 fuel pressure regulator control circuit high.

Related Contents:

ISUZU E-IDSS 2024 2019 Engine Diagnostic Service System Free Download

ISUZU IDSS MX2-T Diagnostic Tool

 

 

P0092 DTC Information

1. DTC description

The FRP regulator is installed on the fuel supply pump and controls the fuel amount sucked into the common rail (fuel rail). The FRP regulator is fully opened in the normal state and larger drive current results in a smaller opening of the regulator. The ECM calculates the desired common rail (fuel rail) pressure and the fuel flow rate, and compares the calculated common rail (fuel rail) pressure to the actual pressure value to determine the opening position of the FRP regulator. If the actual common rail (fuel rail) pressure is higher than the desired pressure, the FRP regulator closes to decrease the fuel flow rate. If the ECM detects an excessively high feedback current in the FRP regulator, the DTC is set.

2. Condition for setting the DTC

Preconditions

・The FRP regulator drive duty is 10% to 90%.

Setting conditions

・The ECM detects that the feedback current of the FRP regulator is 2,400 mA or more, or more than the desired current by 1,000 mA or more.

3. Action taken when DTC sets

・Failure is indicated* in the monitor on the machine, or the diagnostic light illuminates.

Note: *Depending on the machine manufacturer, a failure may not be indicated.

・The ECM limits the fuel injection quantity. ・The ECM limits the engine speed. ・The ECM stops multi-injection.

 

P0092 Diagnostics

Note: If the FRP regulator high-side circuit is shorted to the power supply, the engine stalls and does not start.

1. OBD system check
2. Current DTC check

Turn OFF the ignition switch for 30 seconds or more.

Turn ON the ignition switch.

Observe the DTC information with a trouble diagnosis scan tool. Is DTC P0092 set?

Yes

⇒Go to Inspection for short to power supply in FRP regulator high-side circuit.

No

Go to Intermittent conditions of engine.

 

Inspection for short to power supply in FRP regulator high-side circuit

Turn OFF the ignition switch.

Disconnect the FRP regulator harness connector.

Disconnect the ECM harness connector.

Connect a test lamp between the FRP regulator valve high-side circuit and the frame ground.

Turn ON the ignition switch. Does the test lamp illuminate?

Yes

Repair the short to the battery power supply circuit or the short to the ignition power supply circuit in the high-side circuit between the ECM and the FRP regulator.

⇒Go to Repair verification.

No

⇒Go to Inspection for short to power supply in FRP regulator low-side circuit.

 

Inspection for short to power supply in FRP regulator low-side circuit

Connect a test lamp between the FRP regulator valve low-side circuit and the frame ground.

Turn ON the ignition switch. Does the test lamp illuminate?

Yes

Repair the short to the battery power supply circuit or the short to the ignition power supply circuit in the low-side circuit between the ECM and the FRP regulator.

⇒Go to Repair verification.

No

⇒Go to Inspection for short circuit in FRP regulator circuit.

 

Inspection for short circuit in FRP regulator circuit

Inspection for short circuit in FRP regulator circuit Is the result normal?

Yes

⇒Go to ECM replacement.

No

Repair the circuit as necessary.

⇒Go to Repair verification.

 

ECM replacement

Note: Perform programming after replacing the ECM.

Procedure completion

⇒Go to Repair verification.

 

Repair verification

Clear the DTC with a trouble diagnosis scan tool.

Turn OFF the ignition switch for 30 seconds or more.

Start the engine.

Perform a test-run under the conditions for running the DTC.

Observe the DTC information with a trouble diagnosis scan tool. A DTC should not be set.

 

More repair cases for ISUZU engine,please refer to:ISUZU Engine Trouble Repair