Contour Enthusiasts Group Archives Forums General Troubleshooting Fault code definitions

On a recent vacation to your fine country, I purchased an Actron OBD2 fault code reader (handy tool, but don't seem easy to find in the UK!). However, on returning home I tried this on my 1999 Mondeo ST24 (2.5l Duratec) and it throws up the following codes;
P0320 (Ignition/Distributor Engine Speed Circuit Malfunction)
P1131 (Lack of H02S1 Switches Lean)
Can anyone help with where I should start looking to solve these?

Thanks

For DTC P0320:

The following is from the Ford TSP:

Continuous Memory Diagnostic Trouble Code (DTC) P0320 indicates two successive erratic Profile Ignition Pickup (PIP) pulses occurred resulting in a possible engine miss or stall.

Possible causes:
-- Loose wires/connectors.
-- Arcing secondary ignition components (coil, wires, plugs, etc.).
-- On-board transmitter (2-way radio).*

*Verify all 2-way radio installations. Carefully follow manufacturer's installation instructions regarding the routing of antenna and power leads.

For DTC 1131:

The following is from the Ford TSP:

Diagnostic Trouble Codes (DTCs) P1131 bank (1) (Cylinder #1) and P1151 bank (2) indicate the fuel/air ratio is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt. DTCs P1132 bank (1) (Cylinder #1) and P1152 bank (2) indicate the fuel/air ratio is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.

DTCs P1130 and P1150 indicate the fuel control system has reached maximum compensation for a lean or rich condition and the HO2S is not switching.

DTC/HO2S Reference List
-- HO2S-11 = DTCs P1131, P1132 and P1130
-- HO2S-21 = DTCs P1151, P1152 and P1150

Possible causes:

Fuel system
-- Excessive fuel pressure.
-- Leaking fuel injector(s).
-- Leaking fuel pressure regulator.
-- Low fuel pressure.
-- Contaminated injector(s)

Induction system
-- Air leaks after the MAF.
-- Vacuum leaks.
-- Restricted air inlet.
-- PCV system.
-- Fuel purge system.
-- Improperly seated dip stick.

EGR
-- Leaking gasket.
-- Stuck open EGR valve.
-- Leaking diaphragm.

Base engine
-- Oil overfill.
-- Cam timing.
-- Cylinder compression.
-- Exhaust leaks before or near the HO2Ss.

* Check air intake for leaks, obstructions and damage.
* Check air filter, air filter housing for blockage.
* Verify integrity of the PCV system.
* Check for vacuum leaks.

This also might be helpful.

http://www.obdii.com/codes.asp

I would bet a P1131 is the upstream bank #1 oxygen sensor. I had a P1131 code and when I replaced this sensor the code went away. It could be something else but I would start there. I would recommend using the search feature on this site; there is a wealth of information on this subject.