Fix P2228: Mechanic’s solutions that WORKED

The code P2228: Barometric Pressure Sensor Circuit Low Voltage indicates an issue with the barometric pressure sensor circuit, specifically signaling that the voltage input is lower than expected. This sensor measures the atmospheric pressure and helps the engine’s control unit to adjust the air-fuel mixture and ignition timing. A low voltage signal from this sensor can lead to incorrect engine adjustments, affecting performance and emissions.

P2228 quick overview

Meaning	P2228: Barometric Pressure Sensor Circuit Low Voltage
Is it serious?	Yes, this code can be serious as it may affect engine performance, fuel efficiency, and emissions.
Possible causes	– Damaged or faulty barometric pressure sensor – Short or open in the sensor’s wiring – Poor electrical connections in the sensor’s circuit – ECM/PCM issues affecting the sensor’s operation
How to diagnose?	Check Sensor and Wiring: Inspect the barometric pressure sensor and its wiring for any visible damage or disconnections. Test Sensor Functionality: Use a multimeter to test the sensor’s voltage and ground signals. Inspect Connectors: Look for corrosion or poor connections at the sensor’s electrical connector. Review Related Codes: Analyze any other diagnostic trouble codes that may be related to the barometric pressure system. Consult Technical Service Bulletins: Look for any manufacturer bulletins that might provide insight into common issues and fixes for your specific vehicle model.

How to fix P2228 – learn from mechanics

I looked into P2228 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Honda

Vehicle Information:
2004 Honda Accord EX 3.0L – Poor Idle Quality, Hesitation, Surge, MIL Lamp on

Issue + Repair History:

• Vehicle only idles, with no response from the accelerator pedal.
• Customer replaced the Accelerator Pedal Position (APP) sensor, suspecting it to be the problem.
• Multiple sensors showing codes for low voltage; data stream showing 0.00 for every Parameter ID (PID), with extreme temperature readings for ECT and IAT.
• All 12v signals to PCM and 5v signals from PCM are present.
• Comprehensive checks on connections, splice packs, engine, transmission, and body grounds were conducted.

Other OBD2 Codes + Test Results:

• P2122: APP sensor A low voltage
• P2127: APP sensor B low voltage
• P0107: MAP sensor circuit
• P0117: ECT sensor low
• P0112: IAT current low
• P2228: Baro circuit low

Suggestions to Fix Issue:

• Scope the components generating the codes to pinpoint issues.
• Confirm 5v at each sensor and check if the return voltage differs from the 5v reference.
• Ensure each sensor has a proper ground.
• Consider PCM issue if all voltages are correct but problems persist.
• Clean the throttle body and manually or electronically test its responsiveness.
• Check the charging system and throttle body cleanliness.
• Verify all wiring and connections thoroughly for potential faults.

Final Fix:
The issue was resolved by replacing the PCM with a new factory unit, which restored accurate data and vehicle functionality.

Case #2: Dodge

Vehicle Information:
2007 Dodge Ram 3500 ST 6.7L – Stall

Issue + Repair History:

• The truck experiences a loss of power during acceleration.
• Eight codes appear simultaneously upon cranking the engine: P2262, P0471, P0102, P1193, P2228, P2229, P2580, P2509, indicating various sensor and turbocharger issues.
• All 5-volt references and sensor grounds checked and are reading correctly.
• PCM power and grounds confirmed as good.

Suggestions to Fix Issue:

• Consider the oddity of conflicting codes (e.g., Baro high and low at the same time) and assess for a wiring issue or an ECU internal fault.
• Check for shorts, especially if the engine was recently washed.
• Measure PCM powers and grounds while cranking to confirm stability under load.
• Try starting the vehicle with all sensors unplugged, then reconnecting one at a time to isolate the issue.
• Reflect on the high failure rate and repair challenges of the PCM in similar models.

Final Fix:
The problem was resolved by replacing the PCM after ensuring all readings and connections were appropriate. The customer’s decision to replace the PCM led to a fully functional vehicle.

Case #3: Chevrolet

Vehicle Information:
2004 Chevrolet Silverado 3500 LS 6.6L – MIL Lamp on

Issue + Repair History:

• The vehicle has been in and out of shops for 8 months and recently died after starting and wouldn’t restart.
• Fuel pressure was significantly lower than desired during cranking.
• After checking, the fuel pressure mysteriously improved, leading to the discovery of a degraded connector at the fuel pump and misrouted wiring from a previous repair.
• The fuel pump was replaced, and the wiring harness was rerouted, which seemed to solve the issue until the check engine light appeared 45 minutes after the customer left.

Other OBD2 Codes + Test Results:

• U0106: Loss of communication with glow plug module
• P2068: Fuel gauge low
• P2227: Barometric pressure sensor performance
• P2228: Barometric pressure sensor voltage low
• Fuel pressure at idle: 4350
• Barometric pressure: 30.14 psi

Suggestions to Fix Issue:

• Check for water intrusion in connectors, especially if the vehicle has been through water.
• Drive and monitor which codes return, then follow the diagnostic chart for those specific codes.
• Consider fuel system issues, such as vacuum leaks from the high-pressure pump back to the tank.
• Check for wiring issues, particularly a common wire or ground for the sensors involved.
• Inspect EGR port for restrictions and clean if necessary.
• Monitor for air in the fuel system and pressure test the supply side for leaks.

Final Fix:
After clearing codes and performing several long road tests, the recurring code P2227 led to checking the EGR port, where a restriction was found. Cleaning the ports removed the restrictions, and no codes returned. The customer has been driving the vehicle for a couple of days without issues, marking the problem as resolved.

Case #4: Chrysler

Vehicle Information:
2004 Chrysler Sebring Limited 3.0L – Mechanical issues

Issue + Repair History:

• Initially replaced the MAF sensor due to scanner codes (P0113, P0102, P2228).
• Vehicle idles and runs well when cold but fails to idle or drive once warm.
• Coolant temperature sensor checked: 6.5 kohms at 32°F.
• Idle Air Control (IAC) tested and replaced with a known good one, but no change.
• Throttle Position Sensor (TPS) readings were off; replaced but didn’t resolve the issue.
• No new codes appeared during diagnostics.
• Finally, discovered that the Multi-Fuel Injector (MFI) relay, also known as the “auto shut off” relay, was inserted backward.

Suggestions to Fix Issue:

• Check the wiring harness for overheating, as it may cause shorts when hot.
• Consider the possibility of a clogged catalytic converter, as it can sometimes cause issues that appear related to the MAF sensor and affect fuel trim.

Final Fix:
The issue was resolved when the MFI relay, which had been inserted backward by the owner in an attempt at self-repair, was corrected. After this adjustment, the vehicle ran without issues.

Case #5: Chevrolet

Vehicle Information:
2012 Chevrolet Equinox LT 2.4L – Surge, Misfire, MIL Lamp on

Issue + Repair History:

• Initially came in non-running; diagnosed with a loose cam chain causing bent valves.
• Replaced the head with a remanufactured one, both timing chains, guides, tensioners, and the exhaust manifold.
• The vehicle ran well for a week before starting to surge and misfire.
• The issue began with the engine at operating temperature, with the computer commanding high-pressure fuel to 0 but the pressure reading upwards of 2000 psi.
• The problem temporarily resolved when raising the throttle off idle but returned once back to idle.

Computer Codes & Descriptions:

• P0014: Exhaust Camshaft Position System Performance
• P0089: Fuel Pressure Regulator Performance
• P0013: Intake Air Temperature Sensor Circuit High Voltage
• P0300: Engine Misfire Detected
• P2228: Barometric Pressure Sensor Circuit Low Voltage
• P228D: Fuel Pressure Regulator 1 Control Performance (only code that returned after clearing)

Other Test Results:

• Low Fuel Pressure: 49 – 55 psi running
• High Fuel Pressure: 450 – 500 psi idling correctly, 1800 – 2200 psi idling badly

Suggestions to Fix Issue:

• Load test the positive side of the fuel pressure regulator.
• Check ground wires, especially those connected to the head for the coils.
• Double-check oil level and type and consider other potential issues like cam phaser or control solenoid problems.
• Examine the connection at the high-pressure fuel pump for any issues.
• Consider replacing the high-pressure fuel pump, especially if it’s part of a manufacturer campaign.

Final Fix:
The issue was resolved by replacing the high-pressure fuel pump. It was determined that when the pump heated up, it failed to control the fuel pressure, allowing it to approach 2500 psi. This replacement corrected the surging and misfire issues.

Advice	Diagnostic Step Description
Check Wiring Harness	Look for any signs of overheating or shorts in the wiring harness as it may cause sensor malfunctions, especially when hot.
Double-Check Sensor Installations	Ensure all sensors, especially those recently installed or replaced (like the MAF, TPS, or barometric pressure sensor), are properly connected and functioning as intended.
Confirm Ground Connections	Verify that all ground connections are secure and intact, particularly for sensors and ECUs, as poor grounding can lead to erratic readings and false codes.
Inspect Fuel System	Examine the fuel pressure and the condition of the fuel pump, especially the high-pressure fuel pump, as incorrect fuel pressure can trigger P2228 among other codes.
Review Previous Repairs	Evaluate any recent repairs or replacements that could have inadvertently affected sensors or wiring, such as misrouted wires or improperly installed components.
Conduct Load Tests	Perform load tests on relevant circuits, particularly the power supply to the fuel pressure regulator or sensors, to check for excessive current draw or compromised supply which could affect sensor readings and lead to a P2228 code.
Recheck All Related Codes	Analyze all related diagnostic trouble codes (DTCs) and their potential interrelations, as solving one might help in addressing P2228, especially if it’s a result of a cascade of malfunctions or misreadings from other sensors or systems.