Ford Fault Codes

I have a 1993 ford taurus 3.8L V6 automatic. I retrieved these fault codes from my car: Code 157, mass air flow sensor fault, low voltage, Code 172, HEGO(HO2S) sensor fault, Code 452, vehicle speed sensor (VSS) signal fault. What are these codes telling me? What is wrong with my car?

They’re telling you that you have a couple of problems. The mass air fault is probably either a dirty or faulty MAF sensor. This is the sensor that is on the intake tube, just after the air filter, which tells the ECM how much air is being brought in to the motor.

The HEGO (Heated Exhaust Gas Oxygen sensor) fault could be one of a couple of things. Either the sensor itself is bad, or the engine is running poorly and the sensor is reading a constant lean (172 is a persistent lean mixture code.) Don’t worry about this one until you fix the other two.

The VSS fault can really only be one thing, and that’s a faulty vehicle speed sensor. Fairly easy to replace.

Before you rush out to get this stuff replaced, you might look in to the condition of the engine wiring harness. To have three sensor faults like this, kind of leads me to wonder if there’s something larger at work here. But like I said, the O2 sensor fault could well be because the engine is running poorly (likely because of the MAF and VSS problems) so I wouldn’t worry about it until you get the other two worked out.