In this tutorial, I'll explain how to test the mass air flow (MAF) sensor on the 1995-1997 3.0L V6 Ford Ranger.
The four tests described in this tutorial are performed using a multimeter, you don't need a scan tool (although it's an amazing tool to have).
Contents of this tutorial:
- Common Symptoms Of A Bad Ford MAF Sensor.
- MAF Sensor Circuit Descriptions.
- TEST 1: Making Sure The MAF Sensor Is Getting Power.
- TEST 2: Making Sure The MAF Sensor Is Getting Chassis Ground.
- TEST 3: Making Sure The MAF Sensor Is Getting Ground (PCM).
- TEST 4: Testing The MAF Signal.
- More 3.0L Ford Ranger Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Sensor MAF (1995-1997 3.0L V6 Ford Ranger) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 3.0L Ford Ranger: 1995, 1996, 1997.
- 3.0L Mazda B3000: 1995, 1996, 1997.
NOTE: The following tutorials will help you test the MAF sensor on the 1990-1994 and 1998-2001 3.0L Ford Ranger:
- How To Test The MAF Sensor (1991-1994 3.0L V6 Ford Ranger).
- How To Test The MAF Sensor (1998-2001 3.0L V6 Ford Ranger).
Common Symptoms Of A Bad Ford MAF Sensor
When the MAF sensor fails, fuel injection computer will illuminate the check engine light and register one of the following MAF sensor trouble codes:
- Code 26: MAF Out Of Self-Test Range.
- Code 56: MAF Circuit Above Maximum Voltage.
- Code 66: MAF Circuit Below Minimum Voltage.
- Code 157: MAF Circuit Below Minimum Voltage.
- Code 158: MAF Circuit Above Maximum Voltage.
- Code 159: MAF Out Of Self-Test Range.
- P0102: MAF Signal Low Input to PCM.
- P0103: MAF Signal High Input to PCM.
- P1100: MAF Circuit Intermittent Voltage Input.
- P1101: MAF Sensor Circuit Output Voltage Low During KOEO Self Test.
You'll also notice engine performance issues. The following list, although not exhaustive, lists the most common symptoms you'll see:
- MAF sensor malfunction that DOES NOT light up the check engine light (CEL).
- Lean or rich air-fuel mixture diagnostic trouble code.
- Fuel trim diagnostic trouble code.
- Lack of power when accelerating the engine under load.
- Black smoke coming from the tail-pipe.
- Bad gas mileage.
- Engine idles rough and stalls.
MAF Sensor Circuit Descriptions
The MAF sensor on the 1995 through 1997 3.0L V6 Ford ranger has a 4-wire connector.
The following table contains a brief description of each:
|D||Light blue with red stripe (LT BLU/RED)||MAF Signal|
|C||Tan with light blue stripe (TAN/LT BLU)||Ground (provided by PCM)|
|B||Black with white stripe (BLK/WHT)||Chassis Ground|
|A||Red (RED)||12 Volts|
TEST 1: Making Sure The MAF Sensor Is Getting Power
The MAF sensor requires 12 Volts to function and it's the red (RED) wire of the MAF sensor connector that provides them.
If you look at the photo above, I've marked the RED wire with the letter A.
We'll run a voltage test on the RED wire to check it for the presence of 10 to 12 Volts DC.
These are the test steps:
Disconnect the MAF sensor from its electrical connector.
Place your multimeter in Volts DC mode.
Connect the red multimeter test lead to the RED wire of the MAF sensor connector.
The RED wire is labeled with the letter A in the photo above.
NOTE: This test is done on the engine wiring harness connector. This connector has round male terminals.
Connect the black multimeter test lead probe the battery negative (-) terminal.
Turn the key ON but don't crank or start the engine.
You should see 10 to 12 Volts on the multimeter.
CASE 1: The RED wire is supplying 10 to 12 Volts. This is the correct result.
On to the next test: TEST 2: Making Sure The MAF Sensor Is Getting Chassis Ground.
CASE 2: The RED wire IS NOT supplying 10 to 12 Volts. Without this voltage the MAF sensor will not function.
The most likely cause of this lack of 10 to 12 Volts is an open-circuit problem in the RED wire.