P0202: Cylinder 2 Injector Circuit Malfunction / Open Circuit
Diagnostic Trouble Code (DTC) P0202 indicates that the Engine Control Module (ECM/PCM) has detected an electrical circuit discontinuity, open circuit, or abnormal current profile in the dedicated fuel injector control circuit for Cylinder 2. In modern common rail diesel engines, the ECM fires each injector using an internal high-voltage boost capacitor (80V-90V for electromagnetic solenoid injectors, or 140V-200V for piezo crystal actuators) with peak pull-in currents of 20 to 30 Amperes. DTC P0202 is triggered when the ECM's internal current-sensing shunt resistor detects zero current (<0.05 A) during commanded firing, an out-of-range inductive kickback voltage spike, or excessive electrical resistance in the Cylinder 2 circuit for more than 2 to 4 consecutive engine revolutions.
🚗 Operational Safety, Typical Repair Costs & Diagnostic Verification
- 01
🚦 Driving Safety & Operational Risk
Immediate mechanical assessment and tow requirementsCylinder 2 Injector Circuit Open - Short Trips to Repair Shop Only
Your Engine Control Unit (ECU) has detected an open electrical circuit on the Cylinder 2 diesel fuel injector. Cylinder 2 is not firing, causing the engine to run with a noticeable cylinder deficit (running on 3 cylinders on a 4-cylinder engine). The vehicle will enter a protective limp mode. You can drive a short distance at low speeds directly to a repair shop, but do not drive long distances or under heavy loads.
MECHANICAL HAZARDS & ENGINE RISK IF DRIVEN:Severe engine vibration damaging dual-mass flywheel (DMF) and engine mounts, unburned diesel fuel washing down cylinder walls, or DPF soot overload. - 02
💰 Typical Workshop Repair Budget
Expected parts replacement and garage labor cost tiersMinor DIY / Filter Purge$30 - $85: Repairing loose injector plug, pin tensioning (pin drag adjustment), or repairing chafed wire pigtail.Sensor cleaning, fuel filter renewal, fuse replacement, or harness contact cleaning.
Sensor / Valve Replacement$180 - $450: Brand-new OEM Bosch, Denso, or Delphi Cylinder 2 diesel injector replacement with new copper crush washer.Single component fix (e.g. pressure regulator valve, inlet metering unit, or reconditioned injector).
Major Overhaul / Pump & Injectors$650 - $1,400: Engine bay injector harness replacement or ECU internal driver stage circuit repair.High-pressure injection pump overhaul, new OEM injector set, or DPF assembly replacement.
- 03
🧰 Initial Visual & Physical Verifications
5-minute zero-tool garage triage steps before calling a workshop1With engine OFF, unplug the Cylinder 2 injector electrical connector: use a multimeter to measure coil resistance across the two injector terminals (Bosch solenoid injectors typically measure 0.2 to 0.6 Ohms; piezo injectors typically measure 180 to 220 kOhms; an open circuit 'OL' confirms internal injector coil failure).2Measure insulation resistance: probe between either injector electrical pin and the injector metal body (must read above 10 Megaohms; any continuity to ground indicates internal insulation breakdown).3Inspect the Cylinder 2 harness plug: check for broken locking tabs, loose female terminal pins, or oil soaking into the electrical connector. - 04
🛡️ Diagnostic Verification & Mechanic Shield
Exact questions to ask your technician to prevent unnecessary parts replacement"Ask the mechanic to measure the coil resistance on Cylinder 2 and compare it with Cylinder 1 before agreeing to replace all injectors."
"Demand a 'Pin Drag Test' on the harness connector terminals: over 40% of injector circuit fault codes are caused by loose female pins rather than a failed injector."
"When installing a new injector, verify that the technician programs the 6 to 7 character or 20-digit IMA/IQA calibration code into the ECU."
Technical Note: Read these technical questions to your mechanic before approving expensive parts replacements:
30-Second Workshop Triage
- Violent engine shaking, severe shudder, and continuous misfire under idle and driving conditions (running on 3 cylinders)
- Severe loss of vehicle acceleration, sluggish throttle response, and inability to pull uphill loads
- Flashing or steady Check Engine Light (MIL) on dashboard, accompanied by flashing glow plug light and ESP/traction warning
- Internal open circuit or broken coil winding inside the Cylinder 2 fuel injector electromagnetic solenoid or piezo actuator
- Broken, chafed, or severed wiring harness wire between the ECM and the Cylinder 2 injector connector
- Corroded, spread, loose, or burned female terminal pins inside the Cylinder 2 two-pin injector electrical connector
Connect scan tool live telemetry: compare Target Fuel Rail Pressure vs Actual Rail Pressure and log metering valve command PWM duty cycle during idle and road load.
Expensive Diagnostic Pitfall & Technical Reality
P0202 means Cylinder 2 common rail fuel injector has failed internally and must be replaced immediately, along with reprogramming new IMA codes ($450 - $900).
While an open solenoid coil does occasionally occur, in over 70% of real-world P0202 occurrences, the injector itself is 100% functional. The failure is virtually always caused by terminal fretting corrosion inside the 2-pin wiring connector, cracked insulation on the engine rocker harness, or vibration-induced pin spread. Modern common rail engines pulse injectors at up to 150V/20A; even a microscopic 0.5-ohm increase in connector contact resistance causes the ECM's internal peak-and-hold driver circuit to detect a current fault and cut cylinder 2.
Spending $650 on a new injector plus coding labor vs testing coil resistance with a $20 multimeter (reading 0.35 ohms = good) and replacing the $15 harness pigtail connector, saving over $550.
Most Common Engines & Fuel Injection Platforms Affected
This fault code predominantly affects the following common rail diesel platforms. Cross-reference your specific engine family below for verified factory failure modes, key sub-assembly part numbers, and dedicated repair links:
VAG 2.0 TDI (EA189 Common Rail)
Typical Symptom: Flashing coil lamp, violent engine stumble at idle, immediate limp mode
Known Factory Failure Mode: Cylinder 2 injector electrical plug locking tab cracked, allowing plug to vibrate loose and break electrical contact
OE 03L130277B / Bosch 0 445 110 369 Common Rail Fuel InjectorBMW 2.0d / 3.0d (N47 / N57 / M47N)
Typical Symptom: Drivetrain malfunction warning, severe misfire under acceleration, restricted engine speed
Known Factory Failure Mode: Oil seepage from swirl flap mechanism soaking Cylinder 2 injector harness loom and causing dielectric breakdown
OE 13537790093 / Bosch 0 445 110 131 Common Rail InjectorMercedes-Benz 2.1 CDI (OM651)
Typical Symptom: Check engine light illuminated, noticeable engine knock, reduced torque and acceleration
Known Factory Failure Mode: Delphi solenoid injector internal coil solder joint fatigue after high thermal cycles, creating intermittent open circuit
OE A6510704987 / Delphi 28342997 Common Rail Diesel InjectorFord / PSA 1.6 TDCi / HDi (DV6ATED4 / DLD-416)
Typical Symptom: Engine hesitation over bumps, rough idle, loss of acceleration power
Known Factory Failure Mode: Wiring loom rubs through against aluminum fuel filter bracket directly above Cylinder 2 injector
OE 0445110239 / PSA 1980J4 Bosch Common Rail Diesel InjectorCylinder Balance & Injector Deviation Guide
Common rail diesel cylinder balance & smooth running diagnostic guide. Balance rates, mg/stroke deviation, P0263 misfire, compression vs injector test.
Control Circuit & Actuator Logic
1. Dynamic In-Demand Fuel Metering
The common rail fuel injector on Cylinder 2 is actuated via two dedicated wires: a shared high-voltage high-side driver line (common to an injector bank) and an individual low-side switched ground line controlled by a dedicated power MOSFET inside the ECM. To open the injector needle against 2000 bar common rail hydraulic backpressure, the ECM discharges an 80V-200V boost capacitor across the terminals for 150-200 microseconds, generating a rapid 20A-30A current surge. Once the valve unseats, the ECM drops voltage to 12V-14V to maintain opening with a hold current of ~10A-12A before de-energizing to allow the return spring to snap the needle shut.
2. Closed-Loop PID Deviation Monitoring
The ECM driver circuit monitors the rate of current rise (di/dt) and peak current amplitude on Cylinder 2 during every combustion cycle. If an open circuit occurs (broken harness wire, backed-out terminal pin, or open solenoid coil winding), current flow is zero. If the driver circuit detects that current fails to reach calibrated minimum thresholds, the ECM immediately registers P0202. To protect the engine from severe rotational torsional imbalance and catalytic converter/DPF thermal damage, the ECM disables Cylinder 2 fuel injection entirely and triggers Limp-Home Mode.
3. Diagnostic Trap: Normally Open (NO) vs Normally Closed (NC) Valves
The Cross-Swapping Diagnostic Proof: In common rail workshops, never replace an expensive injector for P0202 based on a scan tool code alone! Because an open circuit can exist either inside the injector coil or in the wiring harness/ECM driver, perform the standardized cross-swap: swap the Cylinder 2 injector with Cylinder 1 (recording the respective IMA/QR calibration codes). If the trouble code moves from P0202 to P0201, the injector's internal coil winding is 100% defective. If the code remains on P0202 on Cylinder 2, the wiring harness or ECM output driver is broken.
Electrical & Hydraulic Physical Benchmarks
Step-by-Step Workshop Diagnostic Protocol
Cylinder 2 Injector Coil Resistance & Thermal Stability Test
Turn the ignition OFF and disconnect the Cylinder 2 injector connector. Using a high-precision digital multimeter with lead-zeroing on the lowest ohms scale (200 Ω), measure resistance across the two injector terminals at 20°C. Solenoid injector: 0.20-0.45 Ω; Piezo injector: 180-220 kΩ. An infinite reading (OL) confirms a severed internal coil winding. Measure insulation resistance from both terminals to the injector steel body with a 250V Megohmmeter (must exceed >10 MΩ).
Cylinder 2 Wiring Harness Continuity & Resistance Audit
Disconnect the main harness connector from the ECM. Using wiring schematics, identify the high-side power feed pin and low-side ground driver pin for Cylinder 2. Measure end-to-end resistance from the ECM plug to the Cylinder 2 injector connector: resistance must be less than 0.4 Ω on both wires. Flex and shake the engine harness along the valve cover while measuring to detect intermittent breaks.
Short-to-Ground & Short-to-Power Harness Isolation Test
With the ECM and Cylinder 2 injector disconnected, measure resistance between each harness wire and vehicle chassis ground. Resistance must be infinite (OL). Next, measure resistance between the injector wires and all other pins in the harness, as well as to 12V battery power. Any measurable continuity (<10 kΩ) indicates rubbed-through wire insulation.
Connector Pin Fretting & Mechanical Drag Tension Inspection
Inspect the female terminals inside the Cylinder 2 injector connector with a bright inspection light and 10x magnifier. Look for green copper corrosion, arcing burns, or terminal spread. Insert a new male terminal test pin into each female cavity to check mechanical retention drag force (must exceed 2.5 N). Loose terminal drag causes microsecond electrical disconnects that trigger P0202 under engine vibration.
Oscilloscope Current Clamp Waveform Analysis
Reconnect the injector and attach a high-bandwidth inductive current clamp (set to 0-40A scale) around one of the Cylinder 2 injector wires. Connect the clamp to an oscilloscope and start the engine. A healthy waveform shows a rapid 20A-30A peak pull-in current spike, followed by a flat 10A-12A hold plateau. Zero current confirms an open circuit; an erratic square wave confirms an ECM driver stage failure.
Standardized Physical Cross-Swap Isolation Test
If wiring and coil resistance test borderline, remove the Cylinder 2 injector and swap it with Cylinder 1 (retaining new copper seating washers). Program the respective IMA/QR codes. Clear DTCs and start the engine. If the code shifts to P0201, the injector has an internal thermal failure under high-voltage load. If the code stays on P0202, the fault is 100% in the harness or ECM.
Component-Level BOM: Cylinder 2 Fuel Injection Control Stage & Wire Harness
Cylinder 2 Fuel Injection Control Stage & Wire Harness
0 445 110 369 / 0 445 116 059
High-speed electro-hydraulic injector delivering multiple micro-injection events per combustion cycle
1 928 498 056 / Tyco Junior Power Timer 2-Way
Gold-plated/tin-plated female terminals with positive spring retention locking clips
OEM Heat-Shielded Injector Sub-Loom
Protects injector command lines from constant 120°C hot engine oil splash
Injector Solenoid & Piezo Resistance Inspector
Associated Fuel Injection Components
The following genuine OEM fuel pumps and common rail injectors are verified factory equipment for engines reporting fault protocol P0202. Cross-reference operating pressures and tightening torques before sub-assembly replacement:
0445110131BOSCH
BOSCH 0445110131 Common Rail Injector for BMW 320d / 330d / 530d / 730d / X5 M47N & M57N Euro 3
View Technical Specs & Fitment →0445110239BOSCH
0445110239 Injector: PSA 1.6 HDi Ford 1.6 TDCi Specs
View Technical Specs & Fitment →0445110369BOSCH
0445110369 Injector: VW 2.0 TDI EA189 CFFB CFHC Specs
View Technical Specs & Fitment →095000-5880Denso
095000-5880 Denso Toyota 2KD-FTV Injector: 23670-30050 Data
View Technical Specs & Fitment →28337917Delphi
28337917 Delphi Bobcat D24 Injector: 7030364 Specs & Data
View Technical Specs & Fitment →095000-8340Denso
095000-8340 Denso Mitsubishi 4D56 HP Injector: 1465A367 Data
View Technical Specs & Fitment →Cylinder 2 Injector IMA/QR Calibration & Smooth Running Balance Relearn
Following replacement of the Cylinder 2 fuel injector, injector harness repair, or ECM replacement, complete the calibration protocol:
1. Enter the new 6-to-30 digit alphanumeric calibration code (IMA / QR code) stamped on the top of the new Cylinder 2 injector into the ECM via scan tool.
2. Clear all stored trouble codes and ensure battery voltage is fully charged (>12.5 V).
3. Access scan tool 'Engine Control Module' -> 'Special Functions' -> select 'Reset Cylinder Balance / Smooth Running Adaptation Values'.
4. Start the engine: allow it to idle at full operating temperature (coolant >80°C / 176°F) for 5 minutes without touching the accelerator pedal.
5. Accelerate vehicle smoothly in 4th gear to 80 km/h (2200 RPM), then release throttle completely to coast down in gear to 35 km/h (minimum 8s overrun).
6. Repeat this acceleration and coast-down sequence 4 times to allow the ECM to calibrate zero-fuel pilot injection delivery for Cylinder 2.
Differential Diagnosis & Related Faults
Injector Circuit/Open - Cylinder 1
Identical electrical circuit fault on Cylinder 1; used for physical cross-swapping to isolate whether the failure follows the injector hardware or stays with the vehicle wiring.
Cylinder 2 Injector Circuit Low
Specific low-circuit voltage fault on Cylinder 2, indicating that the driver wire is directly shorted to vehicle chassis ground.
Cylinder 2 Misfire Detected
Direct mechanical consequence: because the ECM cannot fire the Cylinder 2 injector, Cylinder 2 fails to generate combustion torque, setting misfire code P0302.
Workshop Field Case Studies
2015 Vauxhall/Opel Insignia 2.0 CDTI (A20DTH)(176,000 km)
Frequently Asked Technical Questions
What does engine fault code P0202 mean?
Diagnostic Trouble Code (DTC) P0202 indicates that the Engine Control Module (ECM/PCM) has detected an electrical circuit discontinuity, open circuit, or abnormal current profile in the dedicated fuel injector control circuit for Cylinder 2. In modern common rail diesel engines, the ECM fires each injector using an internal high-voltage boost capacitor (80V-90V for electromagnetic solenoid injectors, or 140V-200V for piezo crystal actuators) with peak pull-in currents of 20 to 30 Amperes. DTC P0202 is triggered when the ECM's internal current-sensing shunt resistor detects zero current (<0.05 A) during commanded firing, an out-of-range inductive kickback voltage spike, or excessive electrical resistance in the Cylinder 2 circuit for more than 2 to 4 consecutive engine revolutions.
What are the most common symptoms of P0202?
Violent engine shaking, severe shudder, and continuous misfire under idle and driving conditions (running on 3 cylinders), Severe loss of vehicle acceleration, sluggish throttle response, and inability to pull uphill loads, Flashing or steady Check Engine Light (MIL) on dashboard, accompanied by flashing glow plug light and ESP/traction warning, Heavy puffing of white or grey unburned diesel smoke from exhaust pipe during cold start and acceleration, Strong, pungent odor of raw diesel fuel surrounding the vehicle exhaust and engine bay, Scan tool live data shows Cylinder 2 contribution balance pegged at maximum positive fuel trim (+4.5 to +6.0 mg/stroke).
What causes P0202 on a diesel engine?
Internal open circuit or broken coil winding inside the Cylinder 2 fuel injector electromagnetic solenoid or piezo actuator; Broken, chafed, or severed wiring harness wire between the ECM and the Cylinder 2 injector connector; Corroded, spread, loose, or burned female terminal pins inside the Cylinder 2 two-pin injector electrical connector; Burnout of the internal low-side power MOSFET driver transistor for Cylinder 2 inside the Engine Control Module (ECM); Water intrusion or green corrosion inside the main engine wiring harness bulkhead connector; Valve cover or intake manifold wiring harness pinched to ground under a metal retaining bracket.
Is it safe to drive with code P0202 active?
🔴 Critical: Stop Driving / Immediate Tow Required
How much does it cost to fix fault code P0202?
Typical repair costs for fault code P0202 depend on the underlying root cause and diagnostic tier: Level 1 (Minor / Maintenance): $30 - $85: Repairing loose injector plug, pin tensioning (pin drag adjustment), or repairing chafed wire pigtail. (Sensor cleaning, fuel filter renewal, fuse replacement, or harness contact cleaning.); Level 2 (Component Replacement): $180 - $450: Brand-new OEM Bosch, Denso, or Delphi Cylinder 2 diesel injector replacement with new copper crush washer. (Single component fix (e.g. pressure regulator valve, inlet metering unit, or reconditioned injector).); Level 3 (Major Sub-Assembly): $650 - $1,400: Engine bay injector harness replacement or ECU internal driver stage circuit repair. (High-pressure injection pump overhaul, new OEM injector set, or DPF assembly replacement.). Independent workshop benchmark rates. Data indicates over 70% of occurrences are resolved within Level 1 or Level 2 without replacing entire sub-assemblies.
Can I drive my vehicle with trouble code P0202 active?
No, you should avoid driving except to clear the roadway safely. Driving with an active P0202 means Cylinder 2 is completely dead. The severe rotational unbalance puts intense torsional shock on the crankshaft, timing chains, and dual-mass flywheel (DMF). Furthermore, if the circuit fault is intermittent, unburned fuel entering the exhaust will overheat and melt the expensive catalytic converter and DPF filter.
How do I locate Cylinder 2 on my diesel engine?
On standard inline 4-cylinder engines (VAG TDI, Ford TDCi, BMW 2.0d, Mercedes OM651), Cylinder 1 is almost universally at the front of the engine closest to the timing belt/chain serpentine drive, and Cylinder 4 is at the rear next to the transmission/flywheel. Therefore, Cylinder 2 is the second cylinder from the front timing cover. (Note: On certain French engines like Peugeot/Renault, cylinder numbering is reversed, with Cylinder 1 starting at the flywheel end-always consult vehicle service manuals).
Why do I need to enter an IMA/QR code when replacing the Cylinder 2 injector?
Common rail injectors are manufactured with sub-micron tolerances, but microscopic variations in flow rate and needle response time are inevitable. During factory testing, each injector is tested across several pressure points, generating a precision calibration code (IMA/QR code) that encodes its exact manufacturing offsets. Entering this code into the ECM ensures the computer knows the exact microsecond pulse width required to deliver identical fuel mass into Cylinder 2, preventing rough idle and knocking.