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2005 Mercury Mountaineer P0104 Fault: MAF Sensor Issues and Troubleshooting Guide

Model: 2005 Mercury Mountaineer Fault Code: P0104 Posted: 2017-10-01 10:36

I'm experiencing a persistent P0104 diagnostic trouble code on my 2005 Mercury Mountaineer. After checking the Mass Air Flow (MAF) sensor, I found no obvious faults. I've already cleaned the throttle body, cleared the code, and the issue has returned repeatedly. I'm now considering removing and thoroughly cleaning the throttle body again—however, I'm wondering if there's another root cause. Could the P0104 be related to a faulty MAF sensor or wiring? Any guidance on how to properly diagnose this would be greatly appreciated.

Related fault codes
P0104
Comments (5)
Anonymous 2017-10-01 10:44

What is your vehicle's exact year and model? This helps narrow down potential causes specific to the 2005 Mercury Mountaineer.

Anonymous 2017-10-01 11:23

2005 Mercury Mountaineer

Anonymous 2017-10-01 11:52

The P0104 code indicates a problem with the Mass Air Flow (MAF) sensor circuit. Common causes include faulty MAF wiring, loose connections, or an intermittent signal from the sensor itself. To troubleshoot effectively: check for damaged wiring harnesses, inspect connectors for corrosion or damage, and verify MAF readings under various engine loads. Posting your actual MAF air flow rate data during operation would help confirm if readings are within normal range. Also, share freeze frame data when the code appears—this provides critical context on conditions at the time of fault detection.

Anonymous 2017-10-01 17:27

Commanded throttle actuator: 22.35% Accelerator pedal position F: 29.41% Accelerator pedal position E: 40.39% Accelerator pedal position D: 34.12% Absolute throttle position B: 41.96% Ambient air temperature: 64.4°F Relative throttle position: 14.51% Fuel–Air commanded equivalence ratio: 12850.2 Absolute load value: 62.75% Control module voltage: 14.22 V Catalyst Temperature: Bank 2, Sensor 1: 1587.2°F Catalyst Temperature: Bank 1, Sensor 1: 1587.2°F Absolute Barometric Pressure: 104 kPa Evap. System Vapor Pressure: -979.0 Pa Distance traveled since codes cleared: 5.59 miles Warm-ups since codes cleared: 1 Fuel Tank Level Input: 100.0% Commanded evaporative purge: 83.1% EGR Error: -51.4% Commanded EGR: 52.5% Fuel Rail Pressure (relative to manifold vacuum): 265.05 kPa Run time since engine start: 318 seconds Oxygen Sensor 5 Voltage: 0.14 V Oxygen Sensor 5 Short term fuel trim: 8.59% Oxygen Sensor 1 Voltage: 0.22 V Oxygen Sensor 1 Short term fuel trim: 7.81% Throttle position: 27.5% MAF air flow rate: 57.06 g/s Intake air temperature: 73.4°F Timing advance: 21.5 degrees Vehicle speed: 40.99 mph Engine RPM: 2290.25 rpm Intake manifold absolute pressure: 86 kPa Long term fuel trim—Bank 2: -12.5% Short term fuel trim—Bank 2: 9.38% Long term fuel trim—Bank 1: -13.28% Short term fuel trim—Bank 1: 9.38% Engine coolant temperature: 190.4°F Calculated engine load: 76.5% Data sent from Yahoo Mail on Android

Anonymous 2017-10-02 12:39

To properly diagnose the P0104 code, monitor only MAF air flow and RPM at operating temperature. At idle, a healthy MAF sensor should read approximately 4 g/s, increasing with engine speed—around 50 g/s at 2500 rpm and up to 100 g/s at 4000 rpm. If the P0104 code is present and only one issue exists, try unplugging or removing the MAF sensor (or its connector) after recording a baseline reading. Take another reading afterward to see if the signal changes. This test helps determine whether the fault is due to out-of-range or intermittent MAF readings.