Help! service engine soon light p0102

Steve2003 · Post by **Steve2003** » Sun Jan 22, 2006 7:03 pm

I did the tune up on my truck today, Distributor Cap, Rotor. Plugs and wires. What a pain in the A$$! After I was done I took it for a test drive and the service engine light was on, so I plugged in the HPPIII and the code p0102 came up! Anyone know what that code means? Please

Steve

Post by **HenryJ** » Sun Jan 22, 2006 7:13 pm

What wires did you use?
Check to make sure the intake and breather are correctly attached.

GM Service data wrote:DTC P0102
Circuit Description

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:

* An ignition 1 voltage circuit
* A ground circuit
* A signal circuit

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. DTC P0102 sets if the PCM detects a frequency signal lower than the possible range of a properly operating MAF sensor.
Conditions for Running the DTC

* The engine is running for more than 2 seconds.
* The engine speed is more than 400 RPM.
* The ignition 1 signal is more than 8 volts.
* The MAF sensor frequency is stable for more than 1 second.

Conditions for Setting the DTC

The PCM detects that the MAF sensor frequency signal is less than 1,300 Hz.
Diagnostic Aids

Inspect for the following conditions:

* An incorrectly routed harness. Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
o The secondary ignition wires or coils
o Any solenoids
o Any relays
o Any motors
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 130 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* A resistance of 20 Ohms or more on the ground circuit of the MAF sensor can cause this DTC to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

04crewvt · Post by **04crewvt** » Sun Jan 22, 2006 7:18 pm

p0102= Mass air flow low input. Check to see that you reconnected the MAF sensor after you reattached the air filter hose assembly.

Steve2003 · Post by **Steve2003** » Sun Jan 22, 2006 7:28 pm

Thanks Hj and 04crewvt!

I took the air box stuff apart to get a better reach to the plugs. IT got dark and it is real windy here so I rushed putting it back together. I will look it over in the morning

Steve

Steve2003 · Post by **Steve2003** » Sun Jan 22, 2006 7:37 pm

One more question please. I'm taking my truck in to the dealer tomarrow to have the 4wd fixed, should I put the hp3 back to stock?

Steve

Post by **HenryJ** » Sun Jan 22, 2006 7:39 pm

Yes.

They will use the TechII to analyze the transfercase codes.
It may see the PCM's HPPIII programming as corrupt and reflash the PCM. If that happens you will lose your ability to reprogram with the HPPIII.

HenryJ wrote:What wires did you use?

Steve2003 · Post by **Steve2003** » Sun Jan 22, 2006 10:11 pm

HenryJ wrote:What wires did you use?

Taylor 8mm from summit.

The wind calmed down a little bit here so I got the flash light and went out to my truck and disconnected the air box and the two wires and then reconnected them, the srevice engine light was off this time

plugged the hp3 in and there weren't any codes

I then set it back to factory specs. I am know ready for the dealer

Ya!

Steve

04crewvt · Post by **04crewvt** » Mon Jan 23, 2006 3:46 am

Glad to help - those weatherpak connections sometimes look like they are connected but are not locked in, I have had that happen before. it can be a bear to figure out what's wrong .