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Computer showing codes P0122, P0102
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ErpErp
New User
Oct 24, 2015, 3:42 PM
Post #1 of 5
(1866 views)
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Computer showing codes P0122, P0102
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I have a 1999 ford ranger xlt 2.5L 5-speed manual.
Computer showing codes P0122, P0102
I have replaced both the Throttle position sensor and the Mass Air Flow sensor. I have checked the connections to each and tested with a multi-meter. I have replaced the ECU/ECM with a perfect matching one that was programmed before installation. The truck will start, then die. If gas is given, it will die. If I pull the vacuum line on the far driver side of the intake, and feed Seafoam through it, or any engine air, the truck will run and accelerate with the aid of gas. When the truck does run on its own which happens ever so often, it will fully accelerate if gas is given very very slowly, however this effect will last no more than a few seconds and will then be met with the engine dropping to 4-600 rpm and then dying slowly, any gas given at this point will kill the engine. When running at high rpms for those few seconds, the truck can not take any load, and will die if put into gear. At this point I'm clueless.
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Discretesignals
Ultimate Carjunky
/ Moderator
Oct 25, 2015, 1:13 PM
Post #2 of 5
(1822 views)
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Re: Computer showing codes P0122, P0102
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If you clear the codes from the PCM, do they same codes come right back?
If you unplug the MAF sensor connector and start the engine, does the engine run better?
What were the results of your voltage tests on the MAF and TPS sensors?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Oct 25, 2015, 1:17 PM)
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ErpErp
New User
Oct 25, 2015, 6:03 PM
Post #3 of 5
(1813 views)
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Re: Computer showing codes P0122, P0102
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The same codes return near immediately.
It does not run better.
voltage going in was 13.4v, going out there was the normal slow increase of outbound power with increasing acceleration. I cannot recall the exact numbers, I can find out tomorrow.
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Discretesignals
Ultimate Carjunky
/ Moderator
Oct 25, 2015, 6:42 PM
Post #4 of 5
(1812 views)
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Re: Computer showing codes P0122, P0102
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Was this voltage on the MAP or TPS?
You need to make these measurements with the sensors plugged in and ignition on and/or engine running. You need to back probe the connectors with a volt meter referenced to battery negative.
The MAF:
Red: power from EEC relay.....~12.0 vdc
Black: ground......less than 0.3 vdc
Light blue/red: MAF signal....varies between 0.9 to 4.5 vdc. You shouldn't see anything less than 0.23 vdc. Depending on how much air is flowing through the sensor will determine is voltage output. At idle the voltage should be around 1.0 vdc and will increase as you open the throttle with the engine running. You really need a lab scope to see this signal in real time.
Tan/red: MAF return....should be less than 0.3 vdc.
Code P0102 doesn't necessary set because there is a problem with the MAF or its circuits. Anything that would cause low air flow through the sensor than what the engine controller expects it to be can cause that code to pop up. Ripped intake ducting, blockages in the intake ducting or air box, and or a poor running engine could cause that code to show up.
The TPS:
Grey/red: Ground.... less than 0.3 vdc
Grey/white: TP signal ..varies between 0.7 to 4.5 vdc with ignition on. Voltage increases as you open the throttle and decreases as you close it. If your using a volt meter, you need to open and close the throttle really slow to catch dead spots.
Brown/white: VREF....5.0vdc
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Oct 25, 2015, 6:53 PM)
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ErpErp
New User
Oct 27, 2015, 10:35 AM
Post #5 of 5
(1718 views)
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Re: Computer showing codes P0122, P0102
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After checking the voltages like you said, I noticed the meter jumping around in some areas farther up the wire. I recut the wire and added a small fragment, removed the connecting harness making sure to pull out the pins. I then coated the ouside of the pins and wrapped them in electrical tape to provide a barrier. After hooking the wires with the connectors attached and the new line strait to the MAF, it ran perfectly. The problem I was having seems to be a mixture of cut wire and a bad connecting harness. I thank you very much for your help, if it weren't for your aid I would have never noticed the jumping and voltages.
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