Ripping up Jeep CRD computers just to get the connectors was too pricy. Making your own using 5 minute epoxy is real dangerous as if it sticks to the connector pins, your toast. As far as having back-to-back connectors on the sensors, that really sticks out as "Look at me"!!
It took me all of about 1 1/2 hours to do the whole job of splicing in the wire harness. The cost was some solder and heat shrink, and my new connector. Done.
Now, as far as checking out the circuit, here is what I came up with. NOTE that I have added pin numbers on the schematic for clarity.
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ORM Circuit Checkout
* First disconnect the 10 Ohm resistor. All measurements are done with 12 Volts applied to circuit, Pin 3 = +12V, pin 6 = Ground.
* Test relay by using an Ohm meter between AFC Sensor (Pin 8) to CPU AFC (Pin 7). It should read open. Now ground TCM input (Pin 9) and Ohm Meter reading should read 0 Ohms.
* Apply 12V to CPU EGR (pin 4). Apply ground to CPU AFC (pin 7). With 4 Volts on “From MAF Sensor” Pin 1, you should see 4 Volts on “To CPU MAF Input” Pin 2.
(Optional Equip. Test). Using a signal generator on “From CPU EGR Output” Pin 4, set to a 8ms period, 12 Volt normally high PWM signal. As you increase the pulse width, about every 20% of duty-cycle increase, you should see the “To CPU MAF Input” Pin 2, voltage decrease. There should be 4 steps. (At 4 volts, then 3.45, 3.03, 2.71, 2.45). If this works, then on to the next step.
(Alt. Test, No signal gen.) With +12 Volts on “From CPU EGR” Pin 4, the “To CPU MAF” Pin 2, the voltage should be 4 volts. Now ground the “CPU EGR Output” Pin 4. The “To CPU MAF” Pin 2 voltage should go from 4 volts, to 2.45 volts.
* Place 12 volts on “From CPU EGR Output” pin 4.
(Optional Equip. Test). Using a signal generator on “From CPU AFC Output” Pin 7, set to a 4ms period, 12 Volts normally low PWM signal on “From CPU AFC Output, Pin 7. As you increase the PWM, you should see the “To CPU MAF Input” Pin 2, voltage decrease. There should be 4 steps (from 4 volts, then 3.68, 3.42, 3.20, and 3.0).
(Alt. Test, No signal gen). With ground on “From CPU AFC Output, Pin 7, now place +12 Volts on this pin. The Voltage on “To CPU MAF Input, Pin 2, should go from 4 volts, to 3 volts.
If it passes these tests, then your ready to install.
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