P2C82

Code

Generic P — Powertrain

AIR System Pump Supply Voltage Circuit Bank 1

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 33 RU: 21

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Causes

Blown fuse for AIR pump supply
Failed AIR pump relay or control relay
Open, short to ground, or short to battery in pump supply wiring
Corroded or loose connector at the pump or ground
Failed AIR pump motor
Faulty PCM/ECM driver or internal control module fault

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Reduced or no secondary air injection during cold start — possible increased cold-start emissions
No audible pump noise when system should be operating
Possible stored subcodes or freeze-frame data showing low/high supply voltage
Engine may run richer during cold start or fail emissions test

What to check

Read and record freeze frame and freeze data; note battery voltage at time of fault
Check for related codes (secondary air injection control / flow codes)
Visual inspection of pump harness, connectors, and ground for corrosion, damage, or loose pins
Verify fuses and relays for the AIR pump circuit
Measure battery/resting voltage and alternator charging voltage
Probe pump connector with a multimeter/scan tool to check supply voltage and ground with key ON and during pump command

Signal parameters

Expected supply voltage at pump connector (key ON, engine off): approximately battery voltage ±0.5 V (typically 12.0–13.0 V)
Voltage while pump commanded: approximately battery voltage if direct feed, or switched/PWM voltage as commanded; should not be 0 V or full short to battery when off
Ground resistance from pump ground to chassis:
Typical pump current draw (nominal): commonly 2–12 A depending on pump—consult vehicle-specific spec; current much higher indicates locked/seized motor, much lower indicates open circuit
PCM drive output (if PWM): duty cycle changes when commanded and measured with scope or bi-directional scan data

Diagnostic algorithm

Verify the code with an OBD-II scanner and record freeze frame data and related DTCs.
Check battery and charging system voltage — low system voltage can trigger supply faults.
Visually inspect AIR pump wiring, connectors, and grounds on Bank 1 for corrosion, damage, or loose terminals.
Inspect and test fuse(s) and relay(s) for the AIR pump circuit; replace if faulty.
With key ON (engine off), measure voltage at the AIR pump power terminal and at the pump ground; compare to battery voltage. No or low voltage indicates open or bad fuse/relay/wiring.
Command the pump ON via a bi-directional scan tool (if available) or start engine to the condition where pump should run. Observe voltage at the pump connector while commanded. If the supply is present but pump does not run, suspect the pump.
If voltage is present but pump does not run, bench-test the pump by applying known good battery voltage directly to the pump (observe polarity and use an inline fuse). If pump does not run or draws excessive current, replace pump.
If no supply voltage is present at the pump when commanded, backprobe wiring toward the relay and PCM to locate open or short. Wiggle harness while monitoring voltage to locate intermittent faults.
Check PCM output driver for short to ground or battery; if wiring and components are good and PCM output is abnormal, consult manufacturer guidance for PCM testing/repair.
After repairs, clear codes and perform the required drive cycle or cold-start cycles to confirm the fault does not return.