BOLT 2152589 - Caterpillar

System Operation Description:The control module for the Electronic Ignition System (EIS) has internal circuit drivers for the ignition transformers. Each circuit driver creates a signal of approximately 190 volts. The signal goes to the high side of the primary circuits of the ignition transformers. The transformers deliver high voltage (8000 to 32,000 volts) to the spark plugs.The wiring for the primary ignition circuits is contained in two harnesses. One harness runs between the EIS control module and a bulkhead connector for each valve cover base. Another harness runs between the bulkhead connector and each ignition transformer under the valve cover. This harness is fastened to a fiberglass rod and the harness is supported above the supports for the valve mechanism.If the engine is configured for Canadian Standards Association (CSA), the wiring for the primary ignition circuits is routed through a distribution panel and a length of conduit in order to connect the control module to the bulkhead connector.The wiring for each transformer consists of a high side wire and a low side wire.The control module monitors the wiring and the transformers. The module checks the circuits for these faults:
A short circuit between a high side wire and +Battery
A short circuit between a high side wire and −Battery
A short circuit between a low side wire and +Battery
A short circuit between a low side wire and −Battery
A short circuit between a high side wire and a low side wire
An open circuitAll of the low side wires are connected together inside the control module. A short circuit on one of the low side wires will affect all of the low side wires.Table 1 lists the diagnostic codes that apply to the primary ignition circuits.
Table 1
Diagnostic Codes for the Primary Ignition Circuits    
Code    Conditions Which Can Cause the Code    
300-03     A low side wire is shorted to a positive voltage source.
The control module cannot determine the cylinder because all of the low side wires are connected together. You must determine the particular low side wire that has the short circuit.    
300-04     A low side wire is shorted to ground or −Battery.
The control module cannot determine the cylinder because all of the low side wires are connected together. You must determine the particular low side wire that has the short circuit.    
301-05 through 312-05     There is an open in the primary ignition circuit. The open circuit could be in a wire, in a transformer, or inside the control module.    
301-06 through 312-06     A high side wire is shorted to positive voltage source or to ground. Alternatively, the control module may be faulty or there may be a short in the transformer.    
301-12 through 312-12     A high side wire is shorted to a low side wire.
The transformer may have a short circuit.
Alternatively, the control module may be faulty.    The control module will not shut down the engine for a faulty ignition circuit. The engine will continue to run. However, these conditions