Code
P0416
Generic
P — Powertrain
AIR System Switching Valve B Circuit Open
AI status
Completed
Completed
100%
Causes
- Open or high-resistance wiring in valve B control circuit
- Corroded, loose or disconnected connector at the switching valve or ECM
- Failed AIR switching valve (solenoid)
- Blown fuse or relay powering AIR system
- ECM driver transistor or internal fault
- Mechanical blockage in AIR lines or stuck valve causing abnormal readings
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored P0416 trouble code (may be combined with other AIR codes)
- Possible rough cold idle, increased exhaust smell or visible emissions on cold start
- Failed emissions test (high HC/NOx)
- Secondary air pump may run incorrectly or not at all
What to check
- Retrieve freeze-frame and pending codes; note any other AIR-related codes
- Visually inspect connector at AIR switching valve B and harness for damage, corrosion, or water
- Check fuse(s) and relay(s) for the AIR system
- Measure resistance of the switching valve coil at the connector (with connector disconnected)
- Check for continuity between the ECM control pin and the valve connector pin; check for short to battery and short to ground
- Backprobe the control circuit while cranking/starting to see if ECM is commanding the valve (voltage pulses)
Signal parameters
- Control: switched 0–12 V (ECM pulses ground or +12 V depending on design)
- Resting (unpowered) coil resistance: typically ~10–50 ohms (manufacturer-specific) — open circuit indicates infinite resistance
- Commanded state: pulse-width modulated (PWM) duty cycle during air injection phase; voltage transitions expected when commanded
- No voltage or open circuit at connector when commanded indicates wiring/valve issue; constant battery voltage may indicate short to power
Diagnostic algorithm
- Verify P0416 with a scan tool; record freeze-frame and additional AIR codes.
- Visually inspect valve B connector and harness for corrosion, damage or water intrusion; repair as needed.
- Check AIR system fuses and relays; replace if blown or faulty.
- Disconnect valve B harness and measure coil resistance; compare to manufacturer spec. If open/infinite → replace valve.
- With connector disconnected, check for short to battery or ground from valve pin(s).
- Backprobe the valve connector while cranking/cold-start with a partner operating the scan tool to command AIR on; observe voltage/pulses. If ECM commands but valve sees no voltage → wiring fault between ECM and valve.
- Check continuity between ECM control pin and valve connector pin. Repair any opens or high resistance (repair splices, replace damaged harness).
- If wiring and valve test good but no command from ECM, check ECM output driver and related grounds/power. Consider ECM bench test or replacement as last resort.
- After repairs, clear codes and perform a few cold starts to confirm AIR operation and that P0416 does not return.
Likely causes
- Damaged harness between ECM and AIR switching valve B (broken wire, chafing)
- Connector corrosion or water intrusion at valve B
- Faulty switching valve (coil open)
- Blown AIR system fuse or defective relay
- ECM output driver failure
Fault status
Status
P0416 — AIR System Switching Valve B Circuit Open. ECM detected an open or high-resistance circuit to the secondary air injection switching valve (Bank B).
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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Code
P0416
GWM
P — Powertrain
- Intake manifold valve B open
AI status
Completed
Completed
100%
Causes
- Open or high-resistance wiring in valve B control circuit
- Corroded, loose or disconnected connector at the switching valve or ECM
- Failed AIR switching valve (solenoid)
- Blown fuse or relay powering AIR system
- ECM driver transistor or internal fault
- Mechanical blockage in AIR lines or stuck valve causing abnormal readings
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored P0416 trouble code (may be combined with other AIR codes)
- Possible rough cold idle, increased exhaust smell or visible emissions on cold start
- Failed emissions test (high HC/NOx)
- Secondary air pump may run incorrectly or not at all
What to check
- Retrieve freeze-frame and pending codes; note any other AIR-related codes
- Visually inspect connector at AIR switching valve B and harness for damage, corrosion, or water
- Check fuse(s) and relay(s) for the AIR system
- Measure resistance of the switching valve coil at the connector (with connector disconnected)
- Check for continuity between the ECM control pin and the valve connector pin; check for short to battery and short to ground
- Backprobe the control circuit while cranking/starting to see if ECM is commanding the valve (voltage pulses)
Signal parameters
- Control: switched 0–12 V (ECM pulses ground or +12 V depending on design)
- Resting (unpowered) coil resistance: typically ~10–50 ohms (manufacturer-specific) — open circuit indicates infinite resistance
- Commanded state: pulse-width modulated (PWM) duty cycle during air injection phase; voltage transitions expected when commanded
- No voltage or open circuit at connector when commanded indicates wiring/valve issue; constant battery voltage may indicate short to power
Diagnostic algorithm
- Verify P0416 with a scan tool; record freeze-frame and additional AIR codes.
- Visually inspect valve B connector and harness for corrosion, damage or water intrusion; repair as needed.
- Check AIR system fuses and relays; replace if blown or faulty.
- Disconnect valve B harness and measure coil resistance; compare to manufacturer spec. If open/infinite → replace valve.
- With connector disconnected, check for short to battery or ground from valve pin(s).
- Backprobe the valve connector while cranking/cold-start with a partner operating the scan tool to command AIR on; observe voltage/pulses. If ECM commands but valve sees no voltage → wiring fault between ECM and valve.
- Check continuity between ECM control pin and valve connector pin. Repair any opens or high resistance (repair splices, replace damaged harness).
- If wiring and valve test good but no command from ECM, check ECM output driver and related grounds/power. Consider ECM bench test or replacement as last resort.
- After repairs, clear codes and perform a few cold starts to confirm AIR operation and that P0416 does not return.
Likely causes
- Damaged harness between ECM and AIR switching valve B (broken wire, chafing)
- Connector corrosion or water intrusion at valve B
- Faulty switching valve (coil open)
- Blown AIR system fuse or defective relay
- ECM output driver failure
Fault status
Status
P0416 — AIR System Switching Valve B Circuit Open. ECM detected an open or high-resistance circuit to the secondary air injection switching valve (Bank B).
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
Similar codes
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Code
P0416
HUMMER
P — Powertrain
Secondary Air Injection System Switching Valve B Circuit Open
AI status
Completed
Completed
100%
Causes
- Open or high-resistance wiring in valve B control circuit
- Corroded, loose or disconnected connector at the switching valve or ECM
- Failed AIR switching valve (solenoid)
- Blown fuse or relay powering AIR system
- ECM driver transistor or internal fault
- Mechanical blockage in AIR lines or stuck valve causing abnormal readings
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored P0416 trouble code (may be combined with other AIR codes)
- Possible rough cold idle, increased exhaust smell or visible emissions on cold start
- Failed emissions test (high HC/NOx)
- Secondary air pump may run incorrectly or not at all
What to check
- Retrieve freeze-frame and pending codes; note any other AIR-related codes
- Visually inspect connector at AIR switching valve B and harness for damage, corrosion, or water
- Check fuse(s) and relay(s) for the AIR system
- Measure resistance of the switching valve coil at the connector (with connector disconnected)
- Check for continuity between the ECM control pin and the valve connector pin; check for short to battery and short to ground
- Backprobe the control circuit while cranking/starting to see if ECM is commanding the valve (voltage pulses)
Signal parameters
- Control: switched 0–12 V (ECM pulses ground or +12 V depending on design)
- Resting (unpowered) coil resistance: typically ~10–50 ohms (manufacturer-specific) — open circuit indicates infinite resistance
- Commanded state: pulse-width modulated (PWM) duty cycle during air injection phase; voltage transitions expected when commanded
- No voltage or open circuit at connector when commanded indicates wiring/valve issue; constant battery voltage may indicate short to power
Diagnostic algorithm
- Verify P0416 with a scan tool; record freeze-frame and additional AIR codes.
- Visually inspect valve B connector and harness for corrosion, damage or water intrusion; repair as needed.
- Check AIR system fuses and relays; replace if blown or faulty.
- Disconnect valve B harness and measure coil resistance; compare to manufacturer spec. If open/infinite → replace valve.
- With connector disconnected, check for short to battery or ground from valve pin(s).
- Backprobe the valve connector while cranking/cold-start with a partner operating the scan tool to command AIR on; observe voltage/pulses. If ECM commands but valve sees no voltage → wiring fault between ECM and valve.
- Check continuity between ECM control pin and valve connector pin. Repair any opens or high resistance (repair splices, replace damaged harness).
- If wiring and valve test good but no command from ECM, check ECM output driver and related grounds/power. Consider ECM bench test or replacement as last resort.
- After repairs, clear codes and perform a few cold starts to confirm AIR operation and that P0416 does not return.
Likely causes
- Damaged harness between ECM and AIR switching valve B (broken wire, chafing)
- Connector corrosion or water intrusion at valve B
- Faulty switching valve (coil open)
- Blown AIR system fuse or defective relay
- ECM output driver failure
Fault status
Status
P0416 — AIR System Switching Valve B Circuit Open. ECM detected an open or high-resistance circuit to the secondary air injection switching valve (Bank B).
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
Similar codes
Repair manuals
Manual library for HUMMER
138
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