P2C26

Code

Generic P — Powertrain

Fuel Injector Group B Supply Sense Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 23 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in the injector group supply/sense wiring harness
Poor or corroded connector pin at injector group supply or PCM
Blown fuse or faulty relay feeding the injector supply
Failed fuel injector(s) causing abnormal circuit loading
PCM/ECM internal driver or sense circuit fault
Water intrusion, corrosion or mechanical damage to connector or wiring

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Engine misfire or rough idle (if multiple injectors in the group are affected)
Decreased engine performance, hesitation or reduced power
Hard starting or extended crank time
Possible fuel odor or increased fuel consumption
Some cylinders may not inject fuel if supply is lost to that group

What to check

Read and record freeze frame and all stored DTCs and pending codes
Inspect related fuses and injector/main relay for continuity and operation
Visually inspect wiring harness and connectors for damage, corrosion, water, or pins pushed out
Check battery voltage and charge state before signal tests
Verify if the code is intermittent — wiggle harness while monitoring live data or looking for code set

Signal parameters

Injector group supply voltage (key ON, engine OFF): approximately battery voltage (~11–14 V) at supply terminal
Injector coil resistance (typical range across various vehicles): approximately 2–16 Ω (low-impedance 2–4 Ω, high-impedance 12–16 Ω) — consult specific service data
Injector driver/sense voltage drops when injectors are actuated (pulse width varies with load): pulse widths typically 1–10 ms depending on engine condition
Backprobe PCM sense pin: stable reference voltage (varies by manufacturer) with expected changes when circuit is switched

Diagnostic algorithm

Capture freeze-frame, pending/related DTCs and current data stream. Note which injectors belong to Group B.
Visually inspect the Group B injector connector(s), harness, and PCM connector for corrosion, bent pins, damaged insulation, or water intrusion.
Check relevant fuses and the injector/main relay for continuity and correct operation. Replace if faulty.
With the ignition ON (engine OFF), backprobe the injector group supply terminal at the harness and verify battery voltage is present. If no voltage, trace back to fuse/relay and battery.
Check continuity between the injector group supply terminal and the PCM supply/sense pin. If open or high resistance, repair wiring or connector as needed.
Measure each Group B injector coil resistance at the harness (disconnected). If any injector is out of expected range or reads short/open, label and replace/test further.
With a noid light or oscilloscope, observe injector drive pulses while cranking/running to confirm PCM is commanding injectors and the supply/sense behavior. Do not perform tests that may cause fuel intrusion or ignition hazards.
If supply voltage is present but PCM sense shows anomaly, check for short to ground or short to battery on the sense wire using resistance and isolation tests (disconnect harness from PCM for safe checks).
If wiring and connectors test good, consider PCM fault: verify PCM power and grounds, then refer to manufacturer service procedures for PCM bench testing or replacement.
After repairs, clear codes and perform a road test/operational checks. Re-scan and confirm the code does not return.

Likely causes

Broken or chafed wire between fuse/relay and injector group B connector
Loose or corroded pin at the injector group B supply connector
Blown EFI/fuel injector supply fuse or failed main injector relay
Short to battery (constant 12V) or short to ground on the supply/sense circuit
Faulty injector(s) presenting abnormal resistance or internal short
PCM power or ground problem or internal PCM injector driver failure

Fault status

⚠️ Status

Fuel Injector Group B Supply Sense Circuit — abnormal voltage, open, or short detected. Inspect injector supply, wiring, connectors, fuses/relay, and PCM.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours