What causes fault code P021E?

• Most likely: Faulty fuel injector (internal open circuit or shorted solenoid coil) • Likely: Wiring harness damage, chafing, or broken wires leading to cylinder 10 • Possible: Corrosion, oxidation, or poor pin tension in the injector connector • Rare: Internal Engine Control Unit (ECU) injector driver failure

Powertrain (Engine & Gearbox)Standard EOBD

P021E - Cylinder 10 Injector Circuit / Open

Q: What are the symptoms of fault code P021E?

• Check engine light (MIL) illuminated • Engine misfire or rough idling • Significant loss of engine power (Limp mode) • Poor fuel economy and hesitation during acceleration • Failed emissions test

Q: How do you fix fault code P021E?

STEP 1: Inspect the connector for injector 10 for oxidation, moisture, or backed-out pins. Clean with contact cleaner if necessary. STEP 2: Measure the resistance (Ohm) of the injector solenoid. Standard values are typically 11-16 Ohms (high impedance) or 0.8-3 Ohms (low impedance). Replace injector if resistance is out of spec or 'OL'. STEP 3: Perform a continuity and short-to-ground test on the wiring harness between the ECU and the injector. Verify 12V supply at the connector with ignition ON. STEP 4: Use an oscilloscope to monitor the injector pulse (waveform) while cranking or idling. If the signal is missing from the ECU despite healthy wiring, the ECU driver may be faulty. STEP 5: Replace the fuel injector and clear fault codes.

Last updated:1 February 2026

Related:Fuel Injector Cylinder 10, Engine Control Unit (ECU/ECM), Wiring Harness (Engine), Fuel Relay

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0200

Injector Circuit Malfunction

P0201

Cylinder 1 Injector Circuit Open

P0202

Injector Circuit - Cylinder 2 - Malfunction

P0203

Injector Circuit - Cylinder 3

Technical Description

P021E is an OBD-II generic code indicating that the Engine Control Module (ECM) has detected a fault in the fuel injector circuit for cylinder 10. This typically refers to an open circuit, high resistance, or a short circuit. The ECM monitors the injector driver circuit for specific voltage and current characteristics. If the inductive kickback (flyback voltage) is not detected or if the current draw is outside of calibrated limits (usually monitored via a shunt resistor or driver IC), the code is stored. This will likely trigger a cylinder deactivation strategy to prevent unburned fuel from damaging the catalytic converter.

Possible Causes

Faulty fuel injector (internal open circuit or shorted solenoid coil)

Wiring harness damage, chafing, or broken wires leading to cylinder 10

Corrosion, oxidation, or poor pin tension in the injector connector

Internal Engine Control Unit (ECU) injector driver failure

Symptoms

Check engine light (MIL) illuminated

Engine misfire or rough idling

Significant loss of engine power (Limp mode)

Poor fuel economy and hesitation during acceleration

Failed emissions test

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P021E - Cylinder 10 Injector Circuit / Open

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P021E - Cylinder 10 Injector Circuit / Open

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