JCB P0202 – ECU: Injector Circuit Open - 2nd Cylinder

The Engine Control Unit (ECU) has detected an electrical open circuit fault in the fuel injector circuit for Cylinder 2. This indicates a break in the electrical path, preventing the ECU from controlling the injector. The ECU identifies this issue when it commands the injector to open but does not detect the expected electrical response, such as a specific voltage spike. This condition can result in a persistent misfire, rough idling, noticeable power loss, engine derate (limp mode), or cause the engine to fail to start or stop while running.

• 3CX
• 4CX
• Telescopic Handlers (Loadalls)
• 1400B
• 1550B
• 1600B
• 1700B
• 214
• 215
• 216
• 217
• 3C
• 3D
• 3DX
• 4C
• 4CN

1. 1

   Visually inspect the wiring harness and electrical connector for the number 2 fuel injector for frayed wires, broken wires, corrosion, or oil/coolant contamination.

2. 2

   Ensure the electrical connector is securely seated on the injector.

3. 3

   Perform a Power Supply Test: Check for steady battery voltage at the injector's electrical connector with the ignition on.

4. 4

   Perform a Circuit Voltage Test using a Noid Light: Plug the noid light into the disconnected harness and crank the engine. A flashing light indicates the ECU control circuit is functioning; no flash or a light that stays on continuously indicates a wiring or ECU issue.

5. 5

   Perform an Injector Resistance Test: Disconnect the injector and measure resistance across its terminals (typically 10-16 Ohms for high-impedance injectors). Infinite resistance indicates a failed coil. You can also compare the resistance value to the other good injectors on the engine.

6. 6

   Swap the cylinder 2 fuel injector with another cylinder (e.g., 1 or 3). If the fault code follows the injector, the injector is faulty. If P0202 returns, the issue is in the wiring or ECU.

1. 1

   Isolate the fault

   Perform the diagnostic checks to confirm whether the fault is with the injector, the wiring, or the connector.

2. 2

   Repair wiring or connector

   If a wiring or connector fault is found, repair or replace the damaged section. Ensure connections are clean and secure, and route repaired wiring away from high heat (like the exhaust manifold) and moving parts.

3. 3

   Replace the fuel injector

   If the injector is faulty, clean the area, disconnect the electrical connector and high-pressure fuel line. Remove the rocker cover (if necessary) and hold-down clamp. Extract the old injector and install the new one with a new sealing washer and O-ring. Torque the clamp to manufacturer specifications, reconnect the line and connector, and reinstall the rocker cover with a new gasket if it was removed.

4. 4

   Calibrate (Code) the injector

   For modern JCB engines (Tier 4, EcoMax), enter the unique calibration code printed on the new injector into the ECU using diagnostic software like JCB ServiceMaster. Failure to do this can result in rough running and persistent fault codes.

5. 5

   Final system checks

   Prime the fuel system according to the manufacturer's procedure, start the engine, check for leaks, clear all fault codes from the ECU, and test drive the machine.