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TX5/MX-6/Probe Engine Management System


It's easy to get you car's ECU to tell you what is wrong with it! I have used this with success. Mechanics that service your car use this method, but only with more expensive equipment that tells you what the problem is. We can extract the 2 digit codes, and use a table to find out what code number represents what problem.

The Probe/Telstar uses two very different types of engine management.  All Telstars/Probes except the 3.0L V-6 use the MECS-I(Mazda Engine Control System) system from Mazda.  The V-6 uses Ford's EEC-IV(Electronic Engine Control) system, which is much more complex than the MECS system.  The wiring diagrams for the two engines are very different, so what works for some Telstars/Probes may not work for others. 

These resust codes are applicable to

This information is correct as far as I know. However, to extract the result codes, the method is slightly different for Australian cars. Ford Probe code extraction is done via Check Engine Light (CEL), whereas the Australian cars, Telstars and Mazdas must use a multimeter or test lamp.

Telstar/Mazda ECU Code Extraction Procedure

KOEO Tests (Key-On, Engine-Off, 2.2L engines only)

To run the self Diagnostic mode: Run a wire from the one wire STI harness (which should be a single black wire with red stripes connected to a green plug) located near the driver's side strut tower (near the wiper motor) to a good ground (I used the strut bolts..). The text isn't too clear, but note that the yellow text indicates the STI, the green the STO, and the purple is the fuel pump test connector. The STI wire should be red with a white stripe. Next, connect a multimeter, or a test lamp (maximum 2 watts) from pin 1 on the large green STO connector (highlighted RED) to the POSITIVE terminal on the battery. Turn the ignition to the 'ON' position, so all dash warning lights illuminate.Using the multimeter or test light the codes will be shown. Long signals are tens, short ones are units. For example, if the light flashes like so LONG wait LONG wait LONG wait LONG wait SHORT, SHORT, the code will be 42, which (using table below) "Turbocharger Boost Control Solenoid (BOOST)".

Sometimes, you may get old codes, because the ECU's memory has not been cleared. To clear codes in a MAZDA or FORD TELSTAR, disconnect the battery, and drpress the brake pedal for 10 seconds, then reconnect the battery, and test by extracting the codes again. To clear codes on a Ford Probe, just disconnect the negative battery terminal for 10min, and reconnect.  Keep in mind that the car will have to relearn it's memory (see owners manual) so if codes are constantly reappearing, then there most likely is a problem.

MECS ECU Diagnostic Codes - 2.2L engine

CODE    EXPLANATION ----    -----------
01      Ignition Diagnostic Monitor(IDM)
02      Crankshaft Position Sensor / 2.2L Turbo(CKP)
03      Crankshaft Position Sensor / 2.2L Turbo (CKP1)
04      Crankshaft Position Sensor / 2.2L Turbo (CKP2)
05      Knock Sensor(KS)
06      Vehicle Speed Sensor(VSS)
08      Vane Air Flow Meter(VAF)
09      Engine Coolant Temperature Sensor(ECT)
10      Vane Air Temperature Sensor-located in VAF (VAT)
12      Throttle Postion Sensor(TPS)
14      Barometric Pressure Switch - 90-92 inside ECU, 89 on firewall
15      O2 sensor voltage below 0.55V - Lean mixture
16      EGR Valve Position Sensor(EVP)
17      O2 sensor stays constantly above 0.55 - Rich mixture
25      Fuel Pressure Regulator Control Solenoid(FPRC)
26      Canister Purge Solenoid(CANP)
28      EGR Control Solenoid(EGRC)
29      EGR Vent Solenoid - Turbo only (EGRV)
34      Idle Speed Control Solenoid Valve(IAC)
42      Turbocharger Boost Control Solenoid (BOOST)
55      Torque Converter Speed Sensor / Pulse Generator
60      Shift Solenoid #1 (non-turbo w/automatic trans)
61      Shift Solenoid #2 (non-turbo w/automatic trans)
62      Shift Solenoid #3 (non-turbo w/automatic trans)
63      Torque Converter Clutch Control Solenoid

Thanks to Bryan for most of this information