Cylinder 2 Injector Circuit Open or Shorted

Common Symptoms

• Engine runs rough or misfires noticeably at idle and under load
• Power output feels noticeably weaker than normal, especially on hills or heavy cuts
• Engine may start hard or stumble before catching on startup
• Fault indicator light or OBD-style fault LED on the mower dash illuminates
• Fuel consumption may increase because the ECM tries to compensate for the dead cylinder
• Engine may exhibit a rhythmic miss rather than a random stumble
• Engine may smell rich or show black smoke if the ECM over-fuels trying to compensate

Probable Causes (Ranked by Likelihood)

• Failed or open-circuit fuel injector coil winding on cylinder 2 Very Likely
• Broken, corroded, or chafed wiring in the cylinder 2 injector harness between the ECM and injector connector Very Likely
• Corroded or backed-out injector connector pins at the cylinder 2 injector plug Likely
• Short to ground in the cylinder 2 injector circuit wire Likely
• ECM driver circuit failure for injector 2 output channel Possible
• Injector connector damaged by heat from the exhaust manifold proximity Possible
• Water intrusion into the injector harness connector causing intermittent short Less Likely

Step-by-Step Diagnostic Procedure

1. Connect the Vanguard EFI diagnostic tool if available and confirm P0202 is the active code. Note whether it is stored or current, as a current code means the fault is present right now.

2. With the engine off and key off, unplug the cylinder 2 injector connector. Visually inspect both the harness-side and injector-side pins for corrosion, green or white residue, bent pins, or signs of melting. Clean any corrosion with electrical contact cleaner before proceeding.

3. Set your multimeter to resistance (Ohms). Measure resistance across the two terminals of the cylinder 2 injector itself. A healthy Vanguard EFI injector reads approximately 12 to 16 Ohms at room temperature. A reading of zero (short) or OL/infinite (open) confirms the injector coil has failed and the injector must be replaced.

4. If the injector resistance tests good, check the harness wiring. With the injector still unplugged, set your multimeter to DC voltage. Turn the key to RUN (do not crank). Probe the harness-side connector: one pin should show battery voltage (12V) as the injector power supply. If you see no voltage on either pin, trace back to the fuse and main injector power relay.

5. Still in RUN with injector unplugged, probe the signal wire pin (the ECM-driven side) to a good chassis ground. You should see near battery voltage sitting high. If you read 0V here, there may be a short to ground in the signal wire. Use the wiring diagram for your specific engine to confirm which pin is signal versus power.

6. Inspect the injector wiring harness along its entire routed path from the ECM to the cylinder 2 location. Look for chafing against the block, zip ties that have worn through insulation, or sections routed too close to exhaust components. Repair any damaged insulation with heat-rated wiring repair materials.

7. If wiring and connector check out and the injector resistance is within spec, suspect the ECM driver channel. Swap the cylinder 1 and cylinder 2 injector connectors if the connectors are physically compatible on your engine configuration, then clear the code and retest. If the fault moves to P0201, the ECM output driver is at fault. This step requires the Vanguard EFI diagnostic tool to clear codes and retest properly.

8. ECM replacement or repair is an advanced step. If diagnostics point to the ECM, contact a Briggs Vanguard authorized service shop, as ECM programming is required after replacement.

Frequently Asked Questions