P2229 – Barometric Pressure Circuit High

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: Circuit High

Definition source: SAE J2012/J2012DA (industry standard)

P2229 indicates the barometric pressure circuit signal is reading higher than expected by the control module. Because the barometric pressure input is used for air-density and altitude-related calculations, a high electrical signal can affect fueling, spark, and other powertrain decisions. DTC behavior, sensor location, and the exact enabling conditions vary by vehicle, so confirm the code’s setting criteria, sensor wiring, and reference values using the correct service information and wiring diagrams before testing. Addressing circuit-high faults typically involves verifying voltage levels, grounds, and unintended power feed.

What Does P2229 Mean?

P2229 – Barometric Pressure Circuit High means the powertrain control module has detected that the barometric pressure circuit voltage is above the expected operating range. Under SAE J2012 DTC structure, this code identifies a standardized powertrain fault and the specific failure mode “circuit high,” which points to an electrical condition such as a short-to-power, a missing ground that drives the signal high, or a sensor/output that is biased high. The code does not, by itself, confirm a failed sensor; it confirms the circuit is electrically high as interpreted by the module.

Quick Reference

  • System: Powertrain
  • Official meaning: Use the official definition provided by the data source for this code.
  • Standard: ISO/SAE Controlled
  • Fault type: Circuit High
  • Risk level: Moderate; incorrect barometric input can degrade drivability and emissions, and may contribute to reduced power on some vehicles.

Symptoms

  • Check engine light: MIL illuminated and P2229 stored as current or pending.
  • Reduced performance: Sluggish acceleration or reduced power due to incorrect air-density calculations.
  • Rough running: Unstable idle or hesitation, especially during throttle transitions.
  • Poor fuel economy: Increased consumption from improper fueling strategy.
  • Hard starting: Longer crank time or difficult starts in some conditions.
  • Black smoke: Rich operation may be noticeable on some engines if fueling is driven high.
  • Additional codes: Other sensor or reference-voltage related DTCs may appear alongside P2229.

Common Causes

  • Short-to-power on the barometric pressure (BARO) sensor signal circuit raising the signal voltage above expected limits
  • Open or high-resistance ground on the BARO sensor circuit causing the signal to bias high
  • Signal circuit open/high resistance (varies by vehicle design) leading to an abnormally high reading seen by the control module
  • Corroded, loose, backed-out, or water-intruded connector terminals at the BARO sensor or control module
  • Sensor 5-volt reference circuit shorted to a higher voltage source or incorrectly shared circuit fault pushing the input high
  • Faulty BARO sensor internal failure producing a persistently high output voltage
  • Harness damage (chafing, pinched wiring) creating intermittent contact with a power feed
  • Control module input circuit fault (less common) interpreting a normal signal as high

Diagnosis Steps

Tools typically needed include a scan tool with live data and freeze-frame access, a digital multimeter, and basic back-probing supplies. A wiring diagram and connector pinout from service information are important because BARO sensing and circuit routing vary by vehicle. If available, use a breakout lead to avoid damaging terminals, and have electrical contact cleaner for inspection findings.

  1. Confirm the DTC and record freeze-frame data (engine speed, load, voltage, altitude/pressure PID if available). Clear codes and see if P2229 resets immediately or only after a drive cycle.
  2. On the scan tool, view live data for barometric pressure and note whether it is fixed at an implausibly high value or spikes high intermittently. If the value is pegged high, prioritize electrical testing for a circuit-high condition.
  3. Perform a careful visual inspection of the BARO sensor (or the sensor location defined by service information) and its harness. Look for chafing, pinched wiring, water intrusion, broken locks, or terminals that appear spread or pushed back.
  4. With key on/engine off, check the BARO sensor connector for obvious issues: corrosion, moisture, or damaged seals. Repair any connector problems first, then clear codes and recheck.
  5. Verify the reference supply at the sensor. Back-probe the reference pin and ground pin and measure voltage with a multimeter. Compare to the specified reference (often around 5 volts, but verify with service info). An unexpectedly high reference suggests a short-to-power or reference circuit fault that can drive the signal high.
  6. Verify sensor ground integrity using a voltage-drop test. With the circuit powered, measure voltage drop from the sensor ground pin to battery negative. Excessive drop indicates high resistance/open ground that can bias the sensor signal high and trigger a circuit-high code.
  7. Check the signal circuit for short-to-power. With the sensor disconnected, measure voltage on the signal wire relative to ground. A significant voltage present with the sensor unplugged indicates the signal line is being driven high (short-to-power, cross-short, or module bias issue). Follow service information to identify normal “bias” voltage if applicable.
  8. Test the signal circuit for continuity and unwanted connection. With power off (as required), check resistance end-to-end from the sensor signal pin to the control module input pin. Also check resistance from signal to battery positive. Low resistance to battery positive indicates a short-to-power; repair the harness.
  9. Perform a wiggle test while monitoring signal voltage and the BARO PID. Gently move the harness near connectors, bends, and known rub points. If the signal jumps high and the code resets, locate and repair the intermittent short or terminal fault.
  10. If wiring, reference, and ground test normal, verify the sensor output behavior per service information. If the signal remains abnormally high under known-good power/ground, replace the BARO sensor and retest.
  11. If the condition persists with a verified-good sensor and verified-good circuits, follow service information for control module input diagnosis. Check for terminal fit issues at the module connector before considering module fault.

Professional tip: When chasing a circuit-high fault, always isolate the sensor by unplugging it and then measuring the signal wire. If the signal voltage stays high with the sensor disconnected, the cause is almost never the sensor itself—focus on a short-to-power, a poor ground creating a biased reading, or a connector/terminal issue along the signal path.

Possible Fixes

  • Repair or replace damaged wiring between the barometric pressure signal circuit and the control module, focusing on shorts to power and rubbed-through insulation.
  • Clean, reseat, and secure the barometric pressure sensor connector; repair loose terminals, corrosion, water intrusion, or poor pin fit that can bias the signal high.
  • Verify and restore correct sensor reference voltage and ground integrity; repair high-resistance grounds, broken ground leads, or shared ground issues that can elevate sensor output.
  • If equipped with a separate barometric pressure sensor, replace the sensor only after confirming the circuit is not being driven high by wiring or reference faults.
  • If the barometric pressure function is integrated into another sensor or module (varies by vehicle), repair/replace the integrated component only after circuit tests prove it is the source of the high signal.
  • Update or reprogram the control module only when service information calls for it and all circuit/sensor checks pass.

Can I Still Drive With P2229?

You may be able to drive short distances if the vehicle feels normal, but treat P2229 as a reliability and drivability risk because a “circuit high” condition can distort altitude/air-density calculations used for fueling, ignition, and boost control (varies by vehicle). Do not continue driving if you notice reduced power, surging, poor throttle response, severe hesitation, stalling, or a no-start condition. If drivability is unstable or the warning light is flashing, stop driving and diagnose the circuit as soon as possible.

What Happens If You Ignore P2229?

Ignoring P2229 can lead to persistent drivability issues, incorrect air/fuel and load calculations, reduced fuel economy, and recurring limp or reduced-power operation depending on strategy. Over time, continued operation with inaccurate pressure input can increase emissions and may contribute to carbon buildup or catalyst stress if fueling control becomes consistently biased. The underlying electrical fault may also worsen (intermittent becomes constant), eventually resulting in stalling, hard starts, or additional sensor-related codes.

Related Codes

  • P2269 – Water in Fuel Condition
  • P2268 – Water in Fuel Sensor Circuit Intermittent
  • P2267 – Water in Fuel Sensor Circuit High
  • P2266 – Water in Fuel Sensor Circuit Low
  • P2265 – Water in Fuel Sensor Circuit Range/Performance
  • P2264 – Water in Fuel Sensor Circuit
  • P2230 – Barometric Pressure Circuit Intermittent
  • P2228 – Barometric Pressure Circuit Low
  • P2227 – Barometric Pressure Circuit Range/Performance
  • P2226 – Barometric Pressure Circuit

Key Takeaways

  • P2229 indicates a barometric pressure circuit high condition, which points first to an electrical signal being driven higher than expected.
  • Most root causes involve wiring/connector problems, shorts to power, or reference/ground integrity issues rather than the sensor itself.
  • Confirm the fault with live data and circuit measurements; a wiggle test and voltage-drop checks are especially useful for intermittent highs.
  • Replace components only after proving the circuit is correct and the sensor output is still high under controlled conditions.
  • Driving may be possible, but worsening drivability, reduced power, or stalling means you should stop and diagnose immediately.

FAQ

Does P2229 always mean the barometric pressure sensor is bad?

No. P2229 is a circuit high fault, so a short to power, poor ground, damaged wiring, or connector pin issues can force the signal high even if the sensor is good. Verify reference voltage, ground quality, and signal behavior before replacing any sensor.

What electrical reading typically confirms a “circuit high” condition?

It depends on the design, but the signal voltage will be abnormally high compared with the expected range and may be close to the sensor’s reference voltage. A fixed high reading that does not respond to key on/engine off changes or normal operating changes is a common confirmation that the circuit is being driven high.

Can a poor ground cause P2229?

Yes. A high-resistance or open ground can raise the sensor’s output or distort the control module’s interpretation, making the signal appear too high. Ground voltage-drop testing under load and careful connector inspection are effective ways to confirm or rule this out.