Code
P0202
HUMMER
P — Powertrain
Injector 2 Control Circuit
Views:
UK: 7
EN: 19
RU: 19
AI status
Completed
Completed
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Causes
- Open or high-resistance wiring between injector 2 and PCM
- Short to ground in injector 2 control (low-side) circuit
- Short to battery/voltage in injector 2 control or supply circuit
- Corroded, loose, or damaged injector connector / terminal
- Faulty fuel injector (internal short or open)
- Blown fuse or poor battery/ignition power to injector feed
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Engine misfire on cylinder 2, rough idle
- Reduced engine power or hesitation under load
- Poor fuel economy and increased emissions
- Difficulty starting or extended crank time (if injector not pulsing)
What to check
- Read stored codes and freeze-frame data with a scan tool; clear code and attempt to reproduce
- Visually inspect wiring and connector for injector 2 for corrosion, damage, pin push-out, or melted insulation
- Check related fuses and main fuel/injection power supply circuits
- Measure injector 2 coil resistance with a multimeter (unplugged) and compare to specified value
- With key ON (engine off) verify battery voltage at injector feed terminal and that voltage is present to all injectors
- Use a noid light or oscilloscope at the injector connector while cranking/running to verify the PCM is commanding injector pulses
Signal parameters
- Injector supply (high-side) voltage: approximately battery voltage with key ON (near 12V)
- Injector control (low-side) signal: PCM grounds the injector to complete circuit (voltage pulled near 0V when commanded)
- Injector coil resistance (typical range): low-impedance injectors ~2–5 ohms, high-impedance ~10–16 ohms (check vehicle spec)
- Pulse width: variable with engine load and RPM (typically ~1–10 ms depending on conditions)
- Pulse frequency: varies with RPM and cylinder firing order; use scope/noid tool to confirm consistent pulsing
Diagnostic algorithm
- Connect a scan tool and record P0202 plus any related codes and freeze-frame data
- Visually inspect injector 2 connector and wiring harness for obvious damage, corrosion, or loose pins; repair as needed
- With ignition OFF disconnect the injector and measure coil resistance; compare to specification to detect open/shorted injector
- With ignition ON (engine off) verify battery voltage at the injector feed (high-side) terminal; if missing, trace supply fuse/relay/wiring
- Backprobe the injector control (low-side) terminal while cranking or running: use a noid light or oscilloscope to confirm PCM is providing a pulsed ground signal
- If no pulse from PCM: check for short to battery on the control wire (would prevent PCM from pulling low) and for short to ground (would show low voltage at rest)
- Perform a wiggle/intermittent test on wiring while observing signal; repair any intermittent/physical faults
- Swap injector 2 with a known-good injector from another cylinder; if code follows the injector, replace it
- If wiring and injector check good and PCM does not command correctly, inspect PCM connectors and grounds; replace PCM only after fully verifying harness and injector failures are not the cause
Likely causes
- Damaged wiring harness or chafed insulation at engine/contact point near injector 2
- Corroded connector pins at injector 2 or harness splice
- Failed injector coil (open or internally shorted)
- PCM output driver fault (less common after wiring & injector verified)
Fault status
Status
P0202 — Injector 2 Control Circuit: PCM detected an electrical fault in the fuel injector drive circuit for cylinder 2 (open, short, or driver fault).
Repair difficulty: Medium
Diagnostic time: 1.0 - 2.5 hours
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