diagnostic codes help ..........12,41, 55

[bouchez101]

i am trying to fix a friends 93 jeep grand cherokee i have fuel pressure at the rail 40psi and spark at the plugs still will not start getting codes 12 41 and 55 only thing that seems weird/out of place "security"light on dash usually flashing does not show up now at all even when doors are opened or key is switched to on position.....any help greatly appreciated thanx again

[legalfee]

41* Alternator field control circuit open or shorted

The power module has an air-cooled resistor which senses incoming air temperature. The logic modules uses this information to control the field current in the alternator. This code applies ONLY to alternators whose voltage is computer regulated. If you lose the feed to keep RAM information stored when the engine's off, you also lose battery voltage sensing.

[esfd455]

Fault Code 41
Synopsis
Description: Alternator field control circuit open or shorted
Power loss light: Off
Limp-in mode: None

Possible Causes
Bad connection or wiring - Check the wiring and connections between the logic module and the power module. Clean and regrease any corroded connectors with dielectric grease and repair any shorts.
Bad voltage regulator circuit - See Diagnosing Your Charging System


Diagnostic Method
Trigger Parameters
- Near 0V or near 12V not detected when the field coil driver is turned on or off, respectively
Results If Component Fails
Fault code 41 is stored. If the condition persists, it will eventually result in a fault code 46 or 47.

[esfd455]

11 IGN reference signal.
12 Battery input to PCM disconnected during last 50 key starts.
13 Fault in the map sensor pneumatic circuit.
14 Fault in the map sensor electrical circuit.
15 Fault in the vehicle speed sensor circuit.
17 Engine running too cool.
21 Problem in the oxygen feedback circuit.
22 Fault in the coolant temperature sensor circuit.
23 Air temperature sensor.
24 Intake air temp. sensor voltage high.
25 Fault in the IAC motor drive circuit.
27 Fault in injector driver interface circuit.
33 Fault in air conditioning cutout relay circuit.
34 S/C solenoid circuits.
35 Fault in fan relay circuit.
41 Fault in the charging system or no field current.
42 Fault in the ASD relay driver circuit.
44 Battery Temp Voltage.
46 Battery voltage is too high.
47 Battery voltage is too low.
51 Lean condition is indicated.
52 Rich condition is indicated.
53 Internal problem in module.
54 No cam position signal.
55 Completion of fault code display.
62 Unsuccessful attempt to update EMR mileage.
63 Unsuccessful attempt to write to an EEPROM location by the controller.

[bouchez101]

thankyou to those who replied to my post very helpful for direction to repair.........ill let you know how i make out a little off topic i also noticed the last time i worked on this jeep (changing fuel pump) that every time i got in the jeep or looked at the dash the orange word "security "was flashing until the jeep was started then it would go out why is it not on now? at all have not seen it .........?