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P1102 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

A P1102 trouble code is stored if the voltage coming from the Mass Air Flow (MAF) sensor to the Powertrain Control Module (PCM) is low but within range.

Meaning

A MAF sensor measures the amount of air flowing into your engine, and it sends that information to the PCM to be processed. MAF sensors are important for controlling fuel injection and ignition timing to optimize power output. If the voltage is lower than expected but still within the manufacturer's stated range, a P1102 trouble code is stored by the PCM and the check engine light comes on.

Causes

The following are common causes of this issue:

  • Faulty MAF sensor
  • Low voltage at the MAF sensor
  • Poor electrical connection at the MAF sensor
  • Short to ground in the wiring harness from the PCM to the MAF sensor
  • Air leak in the vacuum system

Symptoms

The P1102 code will produce a Check Engine Light on the instrument panel/dash and will likely affect:

  • Fuel economy
  • Power output
  • A decrease in throttle response, and an increase in engine hesitation or stalling

Diagnosis

P1102 is properly diagnosed with a scan tool capable of sensor readings (not just one from an auto parts store). A qualified technician can read the data from the scan tool to determine when the problem occurred, or if it is still occurring. They may clear the code/light and test drive the vehicle while monitoring data to see if it returns. If the code returns, then they will know there is still a malfunction. If it does not return, this indicates that the problem has been corrected and the issue is resolved. 

  1. Examine the wiring, connections, and components of the MAF sensor harness for any damaged, loose, or faulty items.
  2. Remove the air filter to check if it needs to be changed.
  3. Remove the MAF sensor gently with a flat head screwdriver while the air filter is out for cleaning.
  4. Replace the MAF sensor and air filter if they have been damaged. If the code remains, clear it and test the system to see whether it continues.
  5. If the trouble code reverts, download any freeze frame data and stored codes.
  6. Before taking it out on the road, perform a smoke test on the vacuum system to look for leaks, especially before and after the MAF sensor.
  7. Connect the digital volt/ohm meter to the MAF sensor and check for a good ground signal and the reference voltage.
  8. If the mechanic finds no voltage or ground signal, they should remove the PCM and other linked modules before checking for continuity with the battery ground. The technician should compare their findings to those provided by the manufacturer.
  9. The technician should also inspect the circuitry between the PCM and MAF sensor for continuity.
  10. The owner of the car may want to take it back to the shop for additional diagnosis. The mechanic should reset and retest the system to see whether the code is stored again.

Common mistakes

The following are possible mistakes if the fix is not complete:

  • Removing the air filter without replacing it 
  • Removing the MAF sensor or performing a smoke test after disconnecting or removing any of its wiring, connections, or components 
  • Reattaching any of the MAF sensor's wiring, connections, and components incorrectly after they have been removed from either end 
  • Incorrectly reconnecting only one side of the MAF harness instead of both sides if it has been disconnected for testing 
  • Not checking for a good ground signal during the replacement process when there may not actually be a fault with it. This can cause further trouble codes to store in memory and affect other sensors on the vehicle. If this happens, technicians will

How serious is this?

The P1102 code will likely affect the vehicle's fuel economy and power output, causing a decrease in throttle response, and an increase in engine hesitation or stalling.

This code is not considered to be serious as it does not affect the safety of the car. However, it may cause some inconveniences for the owner by affecting their driving experience. A qualified technician should diagnose the issue accurately before suggesting a fix or repair.

What repairs can fix the code?

The P1102 code can be fixed by the following repairs:

  • Replacing the MAF sensor 
  • Cleaning or replacing the air filter 
  • Repairing any damaged, loose, or faulty wiring, connections, and components on the MAF harness 
  • Checking for continuity of ground signals between the PCM and MAF sensor 
  • Resetting codes after all repairs are completed/tested to see if it returns. This should clear out unrelated trouble codes stored in memory as well. If they return, further troubleshooting is needed.
  • It is important that technicians do not ignore this trouble code as it may affect other sensors on the vehicle if it remains.

Related codes

P0107, P0108, P0112, P0335, P0336, P0420

How much does it cost to fix the P1102 code?

The cost for a mechanic to fix the P1102 code usually depends on where you are and what type of repair is needed. Most shops will not charge anything under $100 if no further parts or labor need to be purchased. A basic diagnostic fee can range from free to around $70. If more extensive repairs need to be done, it will usually cost around $100 to $300. Special tools may need to be used as well, which will affect the final price of the repair.

Conclusion

Even though this code is not too serious and can be fixed without much trouble, it may affect the vehicle's fuel economy and power output. The P1102 code does not directly affect safety or cause any other codes to be stored that would compromise the car's operation. It should be taken seriously because if it continues to store, further damage could result such as affecting other sensors on the vehicle.

A qualified technician should diagnose the issue before correcting it so as to avoid wasting money on unnecessary repairs or parts. If there are no obvious issues during a smoke test or inspection of the connections between various components, additional diagnosis may be required for complicated cases involving multiple components and subsystems in order to pinpoint where exactly the problem originates from.

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