P022E

Charge Air Cooler Bypass Control B Circuit Low

P022E is a generic OBD-II powertrain diagnostic trouble code: Charge Air Cooler Bypass Control B Circuit Low. It is logged by the engine control unit when the fuel/inj monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P022E
Group
Powertrain
System
Fuel/Inj
Severity
Warning (MIL on, possible limp mode)
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What P022E means

P022E is set when the ECM detects a lower-than-expected electrical value in the charge air cooler bypass control "B" circuit. The "B" circuit designation refers to the secondary bypass control actuator on vehicles with dual-bank intercoolers or two-stage bypass systems; on simpler single-intercooler platforms it may designate a second solenoid on the same bypass assembly. A low-circuit condition means the control signal is present but reading below the acceptable voltage or current threshold set by the ECM's diagnostic calibration — the circuit has continuity but excessive resistance or an underperforming actuator coil is preventing normal current flow. Common sources include corroded connector pins on the bypass solenoid or harness, aged wiring with degraded insulation developing partial shorts to ground, or a solenoid coil that is starting to fail with rising internal resistance. In forced-induction engines the charge air cooler bypass valve allows the ECM to manage intercooler efficiency dynamically; when the "B" circuit operates with below-spec current the ECM cannot reliably position the bypass valve, and boost pressure management on the "B" side degrades. The ECM typically responds by setting P022E, illuminating the MIL, and may implement a power-derate or limp strategy. The low-circuit designation differentiates this code from P022D (open circuit, no continuity at all) and P022F (high circuit, signal above threshold).

Common causes

Most-frequently reported root causes when P022E is logged.

  • 1
    High resistance in the bypass "B" control circuit wiring due to corrosion, partial wire damage, or a degraded splice causing the signal to fall below threshold
  • 2
    Corroded, dirty, or loose connector terminals at the bypass valve or harness intermediate connectors reducing circuit conductivity
  • 3
    Charge air cooler bypass solenoid or actuator coil with elevated internal resistance — the coil winding is degrading but not yet open
  • 4
    Partial short to ground in the control wiring reducing the effective signal voltage at the ECM feedback circuit
  • 5
    Defective or weakened relay or fuse holder with elevated contact resistance supplying insufficient voltage to the actuator
  • 6
    Bypass valve mechanically stuck requiring excessive current to move, causing the drive circuit to appear low to the ECM
  • 7
    ECM driver beginning to fail producing insufficient output voltage or current for the "B" bypass control channel (rare)

Symptoms drivers notice

MIL (Check Engine Light) illuminated with P022E stored; may be accompanied by boost pressure or charge-air temperature fault codes
Reduced engine performance and lower available torque under acceleration, especially at higher boost demands
Vehicle entering limp mode or power-reduction strategy as the ECM limits boost when the "B" bypass circuit cannot be reliably commanded
Engine surging, hesitation, or rough running under load caused by inconsistent charge-air temperature management on the "B" side
Reduced turbocharger or supercharger boost output with the bypass valve unable to achieve the commanded position
Intermittent symptoms or fault code that appears and clears with temperature and vibration changes, indicating a loose or corroded connection

How to diagnose P022E

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and freeze-frame data; note whether P022E appears alone or alongside P022D or P022F, which would suggest the circuit is oscillating through all fault states and points to an intermittent connector or wiring issue
  2. 2
    Inspect the charge air cooler bypass "B" valve connector and the harness routing from the valve back to the ECM for corrosion, heat damage, or chafing; pay particular attention to connector pin condition and locking tab integrity
  3. 3
    Disconnect the bypass "B" valve connector and measure solenoid coil resistance with a DVOM; compare to the manufacturer specification — a resistance significantly higher than spec confirms the coil is degrading
  4. 4
    With the connector disconnected, perform a voltage-drop test on the harness wire from the ECM to the connector terminal, with the ECM commanding the circuit on; excessive voltage drop confirms harness resistance
  5. 5
    Check the supply-side fuse and relay for the bypass "B" circuit; test relay contact resistance and fuse holder continuity, replacing any component with elevated resistance
  6. 6
    Use a scan tool to command the bypass "B" valve through its full range and observe live current or duty-cycle feedback; compare actual current draw to specification to determine whether the fault is in the external circuit or the ECM output
  7. 7
    After all repairs, clear codes and perform a sustained test drive under boost to confirm P022E does not return before returning the vehicle

Related powertrain codes

Frequently asked questions

Is P022E more or less serious than P022D?

Both warrant prompt attention and carry similar drivability impacts. P022D (open circuit) typically means complete loss of control on the "B" bypass valve. P022E (circuit low) may still allow some partial actuation but the ECM cannot confirm correct operation. In terms of fault progression, P022E is often an early indicator of a wiring or actuator problem that will deteriorate into P022D if left unrepaired.

Can cleaning the connector fix P022E?

Yes, in many cases it can. Corroded or dirty connector pins are a common cause of low-circuit codes. Use an appropriate electrical contact cleaner and a pin cleaning tool, inspect for bent or pushed-back pins, and ensure the connector locks securely. After cleaning, clear the code and test drive to verify the repair before assuming the fault is resolved.

What scan tool data should I monitor while diagnosing P022E?

Monitor the bypass valve commanded duty cycle or position alongside the actual feedback value (if available for your platform), the charge-air inlet temperature (before and after intercooler), and boost pressure. A large discrepancy between commanded and actual valve state confirms the circuit cannot follow ECM commands. Also check live sensor voltage for the bypass control circuit if your scan tool supports ECM output monitoring.

Could low battery voltage trigger P022E falsely?

Yes. A weak or failing battery that drops below approximately 11 V during engine cranking or heavy electrical loads can cause marginal control circuits to read below threshold temporarily, setting low-circuit codes. If P022E appears alongside multiple unrelated low-voltage codes, test the battery under load and inspect charging system voltage before pursuing bypass-specific diagnostics.

Disabling P022E in software

RaceTune can permanently disable P022E — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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