Here is a picture of the MAF connector showing the connections: MAF.gif
Here is the MAP connector showing the connections: MAP.gif
And the BARO as discussed is contained within the ECM so no connector there.
I am concerned with the state of charge of the batteries when not running. They should be in the 12.6 - 12.7 range, not 12.2. Yes, they 12.2 batteries will likely start the truck reliably, but they're way undercharged, approx 60%
With key on, engine off, none of the B+ connections should be higher than 12.2 with your batteries. With engine running and alternator supplying voltage, it should be very close to the voltage output of the alternator.
The BARO only shows atmospheric pressure. If the atmospheric pressure where you are goes up, the BARO reading should go up and if atmospheric pressure goes down, the BARO reading should go down. Of course, it you go up a big mountain, the BARO will fall accordingly because atmospheric pressure is less at high altitudes. This appears to be where your problem is, as far as I can tell. But before I changed ECM's, I would change my batteries, clean both ends of all of the battery cables, BOTH ENDS, and also the alternator cable.
MAP shows pressure (or could be negative) inside the intake system which will reflect any boost produced by the turbocharger. This is where your ECM gets it's boost pressure.
So, BARO = Atmospheric pressure (baseline pressure)
MAP = Boost
MAF = Airflow
Sometimes electrical devices will work quite well with a range of voltage inputs, sometimes they won't. Charge your batteries so that after an overnight rest they are fully charged. Then do your BARO test. I don't think that a reflash of the ECM will correct the BARO reading problem, it will take a new ECM and a complete flash with most current updates. Another POSSIBLIITY is to contact a place that revuilds ECM's and see if they can just repair the BARO portion of your existing ECM.
Here is info on P2228: DTC P2228 or P2229 Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.
- Barometric Pressure (BARO) Sensor Circuit Low Voltage
- Barometric Pressure (BARO) Sensor Circuit High Voltage
The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and weather conditions. The sensor translates this action into electrical resistance. The BARO sensor wiring includes 3 circuits. The BARO sensor and all related circuits are inside the engine control module (ECM). The BARO sensor provides a signal voltage to the ECM, relative to the pressure changes on the BARO sensor signal circuit. The ECM converts the signal voltage input to a pressure value. Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56 kPa at an altitude of 4 267 meters (14,000 feet), to 105 kPa at or below sea level. The BARO sensor has a range of 8-207 kPa. The ECM uses the BARO sensor input for fuel delivery and other diagnostics. Conditions for Running the DTC
Conditions for Setting the DTC P2228
- DTC P0652 or P0653 are not set.
- The ignition is ON.
- DTC P2228 and P2229 run continuously when the above conditions are met.
The BARO is less than 60 kPa for 1 second. P2229
The BARO is more than 120 kPa for 1 second. Actions Taken When the DTC Sets
DTCs P2228 and P2229 are Type B DTCs. Conditions for Clearing the MIL/DTC
DTCs P2228 and P2229 are Type B DTCs. Circuit/System Verification Important: If you cannot duplicate the condition, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
- Turn ON the ignition with the engine OFF.
- Observe the BARO parameter with a scan tool.
- Compare the BARO value to the range specified in the altitude vs. barometric pressure table.
- The BARO parameter should be within the range specified in the altitude vs. barometric pressure table.
- Engine running, observe the DTC information with a scan tool. DTCs P2228 or P2229 should not set.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
- Turn ON the ignition, with the engine OFF.
- Observe the BARO parameter with a scan tool.
- Compare the BARO parameter to the range specified in the altitude vs. barometric pressure table.
- If the BARO parameter is outside the range specified, replace the ECM.