P0102 Code on a GMC: MAF Sensor Circuit Low Frequency (GMC Guide)

P0102 on a GMC is "Mass Air Flow (MAF) Sensor Circuit Low Frequency." Most people read "low" as low voltage or low airflow, but the MAF sensors on gas GMC engines send a frequency signal, and P0102 means that frequency fell below what the engine computer will accept — an electrical fault, not a breathing problem. The GMC surprise is a recent one: GM bulletin 24-NA-158 says an active P0102 on the 2023–2024 Yukon with the 5.3L or 6.2L may come from water that got into the MAF connector during assembly, and the fix replaces both the sensor and the connector. On the 2013–2014 Acadia and Terrain V6, GM's documented cause is simpler still: someone unplugged the MAF with the key on.

What Does P0102 Mean on a GMC?

The MAF sensor sits in the air intake duct between the air filter box and the throttle body and tells the engine control module (ECM) how much air is entering the engine. The ECM uses that number to calculate fuel. On many newer GMCs the same housing also contains the intake air temperature sensor and, on some, humidity and barometric pressure sensing.

GM's wording for P0102 is MAF Sensor Circuit Low Frequency. GM's 2001–2006 truck tables for the Sierra, Yukon and Savana V8s describe the test as detecting "a continuous short to low or a open in either the signal circuit or the MAF sensor." GM's 2019 tables for the Sierra and Yukon V8 group describe the newer Continental-built MAF in similar terms: a continuous short to ground in the circuit, or a sensor that is outputting a frequency that is too low.

In plain terms, the ECM is not getting a usable signal on that wire. That makes P0102 very different from P0101, the performance code, where the signal is present but disagrees with GM's airflow model. For that one, see our P0101 GM guide.

A Frequency Code, Not a Voltage Code

The MAF on a gas GMC produces a square-wave signal whose frequency changes with airflow. The ECM counts the pulses. If the signal wire is open or shorted to ground, or the sensor has lost power, the ECM sees few or no pulses — and that reads as a low frequency. GM's GMC truck tables show how the limit has moved over the years:

Look at that last row. On the older sensors, a low frequency meant almost no air. On the Continental MAF used on 2019-era Sierras and Yukons, GM's table says plainly that "a low MAF frequency is associated with a high engine air flow." Either way, a dead or shorted signal produces a frequency below the limit, so the code still points at the circuit — but it is a good reason not to judge a sensor by comparing frequency numbers from a different model year.

The power side matters too. GM's enable conditions require system or powertrain relay voltage to be up; a blown fuse or failed relay can leave the MAF dead and the code set.

Which GMCs Set P0102

GM's tables list P0102 for the Vortec 4.3L, 5.0L, 5.7L and 7.4L trucks from 1997, every Gen III, IV and V small-block V8 in the Sierra, Yukon and Savana, the Canyon's four- and five-cylinders and V6s, and the Terrain and Acadia engines. Two quirks:

• Early Envoy 4.2L. GM's 2002–2005 tables for the 4.2L LL8 inline-six list MAP sensor codes but no MAF circuit codes at all. GM's 2007 table for the LL8 and the Canyon 3.7L LLR group does list P0102 (MAF signal below 900 Hz). If an early Envoy shows P0102 on a generic scanner, double-check the code against a GM-capable tool.
• Duramax diesels. The 6.6L Duramax uses its own P0102 test — GM's 2006 LLY table words it "Circuit Low Voltage" and tests airflow in kg/hr. The diagnosis on a diesel Sierra or Savana is different and is not covered here.

GM documents name P0102 specifically on two GMC groups:

• 2023–2024 Yukon models with the 5.3L L84 or 6.2L L87 — bulletin 24-NA-158, water infiltration in the MAF connector during assembly.
• 2013–2014 Acadia and Terrain with the 3.6L V6 (LLT, LFX) — PI1009, codes set by disconnecting the MAF with the ignition on.

The 2023–2024 Yukon Water Problem

24-NA-158 is a GM technical bulletin for 2023–2024 Yukon models (and the Tahoe, Suburban and Escalade) with the 5.3L L84 or 6.2L L87. Customers may notice a malfunction indicator lamp; the technician finds an active P0102, possibly with U060F and U1346 at the MAF sensor. GM's stated cause is water infiltration into the MAF connector during assembly.

The correction is to replace the MAF sensor and the MAF sensor connector, using a service connector, and to reuse the connector's dress cover. GM's parts list shows MAF sensor 12714453 and engine wiring connector kit 85519071, and the labor time is 1.0 hour. The bulletin was revised in September 2024 to update a part number, so let the dealer confirm the current parts for your VIN. GM references Bumper-to-Bumper coverage for the repair, which depends on your Yukon's age and mileage.

Two practical lessons. First, this is one of the few GM documents for P0102 that does replace the sensor — because water in the connector damages both halves. Second, the bulletin names Yukon models only for GMC; we found no GM bulletin extending it to the Sierra with the same engines, so on a Sierra diagnose the circuit normally.

Acadia and Terrain: the Unplugged Connector

PI1009 covers 2013–2014 Acadia and Terrain (alongside the Chevrolet, Buick and Cadillac twins) with the 3.0L and 3.6L V6 (RPOs LFW, LLT, LFX). GM lists P0097, P00F4, P0113, P2229 and/or P0102 together — every sensor that lives in the multifunction MAF housing. GM says the condition "may be caused by disconnecting the mass air flow (MAF) sensor with the ignition key on and/or the engine running" while servicing the A/C refrigerant fill port, the air filtration system or other underhood components.

GM's instruction is to recheck the connector for proper click engagement and clear all the codes. No part is replaced. The lesson travels to any GMC: if P0102 appeared right after an air filter change, an A/C recharge or other underhood work, look at that connector before anything else.

Symptoms of P0102

• Check engine light — usually after two trips, since GM's truck tables make it a Type B code
• Hesitation, rough running or stalling as the ECM falls back on a calculated airflow
• Possible hard starting
• On a 2023–2024 Yukon: U060F or U1346 alongside it
• On a 2013–2014 Acadia or Terrain V6: P0097, P00F4, P0113 or P2229 alongside it
• Symptoms that come and go with engine movement if a wire is broken inside its insulation

Causes and How to Confirm Each

How Is P0102 Diagnosed?

1. Note every code. Several codes from the same MAF housing point at its connector, power or ground — not at the MAF element. U060F and U1346 on a 2023–2024 Yukon point at 24-NA-158.
2. Ask what was done recently. An air filter change or A/C service with the key on is GM's documented cause on the 3.6L Acadia and Terrain.
3. Have the VIN checked — on a 2023–2024 Yukon with the 5.3L or 6.2L, for 24-NA-158.
4. Reseat and inspect the connector. Make sure it latches and is dry.
5. Watch MAF data at idle. A reading that drops out or jumps with harness movement locates the fault.
6. Check the fuse, supply voltage and ground at the sensor.
7. Test the signal circuit for open and short to ground per the wiring diagram.
8. Replace the sensor last, then clear the codes and confirm over a couple of drive cycles — it is a two-trip code.

Parts and Cost

GMC MAF sensors vary a lot by engine and year — some include intake temperature, humidity and pressure sensing, and the Continental sensor reports differently from earlier ones. Order against your VIN.

GM Documents That Name P0102 on GMCs

Have a dealer check your VIN against current bulletins and campaigns rather than relying on any article, including this one.

What Other P0102 Pages Get Wrong

• "P0102 means a dirty MAF." A dirty element changes the reading; it does not kill the signal. This is a circuit code.
• "Low means low voltage." Gas GMC MAF sensors send frequency. GM's tables test hertz, not volts.
• "Low frequency means low airflow." On the newer Continental MAF, GM's own table says a low frequency is associated with high airflow.
• "Replace the sensor first." GM's Acadia and Terrain fix is to reseat the connector and clear the codes.
• "Every GMC MAF problem is the same." A 2023–2024 Yukon with an active P0102 has a specific GM bulletin; a diesel Sierra uses a different test entirely.

Cadillac Escalade owners will find the same 24-NA-158 story in our Cadillac P0102 guide.

Frequently Asked Questions

Can I drive my GMC with P0102?

Usually, for a short distance. With no usable MAF signal the ECM runs on a calculated airflow, so the engine may hesitate, idle roughly or stall. Get it diagnosed promptly, and avoid long trips or towing if the truck runs poorly.

My 2023 Yukon has P0102. Is there a bulletin?

Yes. GM bulletin 24-NA-158 covers 2023–2024 Yukon models with the 5.3L L84 or 6.2L L87 showing an active P0102, possibly with U060F and U1346. The cause is water in the MAF connector from assembly, and the repair replaces the MAF and the connector. Whether it is covered depends on your warranty; a dealer can check your VIN.

Does 24-NA-158 apply to my Sierra?

The bulletin lists Yukon models for GMC, not the Sierra. A Sierra with P0102 should be diagnosed through the connector, power, ground and signal circuit in the usual order.

Can an air filter change cause P0102?

Yes. GM's PI1009 says unplugging the MAF with the ignition on — during air filter or A/C service — can set P0102 and its companion codes on the 2013–2014 Acadia and Terrain V6. Recheck the connector and clear the codes.

Will cleaning the MAF fix P0102?

Rarely. Cleaning helps a contaminated element, which is more likely to set P0101. P0102 is about a missing or shorted signal, so start with the connector, fuse and wiring.

Why do several codes appear with P0102?

On many newer GMCs the MAF housing also contains intake temperature, humidity and pressure sensors that share the connector. One loose or wet plug can set them all.

Does it matter which MAF I buy?

Very much. GMC MAF sensors differ by engine and year in their functions and in how they signal the ECM, and GM's own frequency limits vary by sensor. Order by VIN and confirm fitment before buying.