Quick question about engine codes

chaka · Apr 12, 2004

Pulled the codes on my 86 F150 302 the other day.

The codes were
23
31
a code for the engine coolant temp.

and a code for the PIP. Changed the PIP and the code disappeared.

However for the TPS. I tested it as the manual said to and it checked out. Why would the code be there?

Also for 31 (EVP out of range) would blocking off the EGR fix this problem. I really don't care about emissions, and was hoping to just have a plate made to insert between the egr valve and the intake. If not what would I have to change/repair to remove the code.

Thanks

jrichker · Apr 12, 2004

Code 23 - Throttle sensor out of range or throttle set too high - TPS needs to be reset to below .99 volts at idle. Keep in mind that when you turn the idle screw to set the idle speed, you change the TPS setting.

CODE: 31 (KOEO) - EVP circuit below minimum voltage. Vref (5 volt reference voltage supplied by the computer) missing or broken wire or bad connection in circuit. Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or MAP sensor located on the firewall near the center of the car. With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Check for the same results on pin 27 on the computer.

Fix the code 31 - you may have some bad wiring/bad connections causing the VREF +5 volts to be absent. A bad or missing VREF could cause both code 23 & code 31.

chaka · Apr 12, 2004

Thanks a lot. I will start tracing wires.

Quick question about engine codes

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Quick question about engine codes

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