G3400 Engines (EIS) Caterpillar

Electrical power is supplied to the control module for the Electronic Ignition System (EIS). Electrical power is also supplied to these optional components:

• Status Control Module (SCM)

• PWM Converter

• Power the sensors.

• Energize the ignition coils.

The Electronic Ignition System (EIS) does not diagnose the power supply. Therefore, the control module will not generate a diagnostic code if the power supply is faulty.

The SCM will generate a 06 dIAG code if the power supply to the SCM is low or unstable. Refer to Systems Operation, SENR6538 for the procedure for troubleshooting this code.

The EIS will generate a 168-02 System Voltage intermittent/erratic if there is a problem with the power supply. The code can be caused by any of these conditions:

• The EIS control module has detected engine rpm during the normal powerup sequence. This will occur if the engine is running and the electrical power is cycled.

• The power supply to the EIS control module is intermittent.

• There is a noisy component in the secondary ignition system.

The ECM will send a shutdown command to the EIS control module if a 168-02 code is generated. The ignition and the fuel will be shut down.

Grounding Practices

Proper grounding is necessary for optimum engine performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and in unreliable electrical circuit paths. Refer to the engine's Operation and Maintenance Manual for additional information on proper grounding practices.

Requirements for the Power Supply

The 24 VDC power supply for the engine can be provided by a battery or by an electrical power supply. The power supply must be capable of providing sufficient current and sufficient voltage in order to start the engine.

The batteries and the battery cables must be the correct size in order to minimize voltage drops. This is particularly important during cranking. The supply voltage at the EIS control module must remain above 18 VDC during cranking. Otherwise, the engine may not start. Random diagnostic codes may be generated by the control module.

The control module requires an instantaneous current flow of at least 16 amperes at a minimum voltage of 18 VDC in order to power up. The EIS control module requires a continuous current flow of at least 3 amperes at a minimum voltage of 18 VDC for continuous operation.

The wiring from the power supply to the modules must provide a maximum voltage drop of 1.0 VDC.

Illustration 1	g01174238
Schematic diagram of the electrical power supply The engine is equipped with a 70 pin connector and EMCP II.

Illustration 2	g01164662
Schematic diagram of the electrical power supply The engine is equipped with a remote control panel.

Test Step 1. Inspect the Electrical Connectors

1. Set the engine control to the OFF/RESET mode. Remove the electrical power from the engine.

   Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".

2. Thoroughly inspect each of the following connectors:
   • EIS connectors on the control module

   • Connectors for the 24 VDC power supply

   • Connectors for the engine control

   1. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the electrical power supply.

   2. Check the harness and wiring for abrasion and for pinch points from the power supply to each module.

Expected Result:

The connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.

Results:

• OK - The components are in good condition with proper connections. Proceed to Test Step 2.

• Not OK - The components are not in good condition and/or at least one connection is improper.

  Repair: Perform the necessary repairs and/or replace parts, if necessary. Ensure that all of the seals are properly installed. Make sure that the connectors are properly fastened. Verify that the repair has eliminated the problem.

  STOP

Test Step 2. Check the Circuit Breakers for Continuity

1. Measure the resistance across each of the circuit breakers.

Expected Result:

The resistance is less than 2 Ohms.

Results:

• OK - The resistance is less than 2 Ohms. The circuit breakers do not have a short circuit. Proceed to Test Step 3.

• Not OK - The resistance of a circuit breaker is greater less than 2 Ohms. A circuit breaker is faulty.

  Repair: Repair the circuit breaker or replace the circuit breaker. Verify that the original problem is resolved.

  STOP

Test Step 3. Check for a Short Circuit

1. Disconnect the following connectors:
   • EIS connectors

   • The "+" and "−" connections for the status control module

2. Disconnect the electronic service tool.

3. Verify that the engine control is in the OFF/RESET mode.

4. Measure the resistance between the following terminal strip connections:
   Show/hide table

   Table 1

   Resistance Measurements for the Power Supply
   Terminal Strip Connection	Terminal Strip Connection
   5 (−Battery)	1 (+Battery)
   	2 (+Battery)
   	102-107 (Keyswitch)

5. Measure the resistance between terminal strip connection 5 and the engine block surface.

   Perform the following procedures on engines that are equipped with a 70 pin connector and a EMCP II.

6. Measure the resistance between the following connections:
   Show/hide table

   Table 2

   Resistance Measurements for the Power Supply
   70 Pin Connection	EMCP II Connections
   44 (−Battery)	Emergency Control Switch
   	RM1

7. Measure the resistance between terminal 44 and terminal 3 of the 70 pin connector.

8. Measure the resistance between terminal 44 and 3 and the engine block surface.

Expected Result:

Each check of the resistance is greater than 2 Ohms.

Results:

• OK - Each check of the resistance is greater than 2 Ohms. The wiring for the power supply does not have a short circuit. Proceed to Test Step 4.

• Not OK - At least one check of the resistance is less than 2 Ohms.

  Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the original problem is resolved.

  STOP

Test Step 4. Check the EIS Control Module for a Short Circuit

1. Connect the EIS connectors.

2. Measure the resistance between terminal strip connections 5 and 103.

   Perform the following procedure on engines that are equipped with a 70 pin connector and a EMCP II.

3. Measure the resistance between terminal 44 and terminal 3 of the 70 pin connector.

Expected Result:

The resistance is greater than 2 Ohms.

Results:

• OK - The resistance is greater than 2 Ohms. The EIS control module does not have a short circuit. If the engine is equipped with a status control module, proceed to Test Step 5.

• Not OK - The resistance is less than 2 Ohms. The EIS control module has a short circuit.

  Repair: Replace the EIS control module. Refer to Troubleshooting, "Replacing the EIS Control Module".

  STOP

Test Step 5. Check the Status Control Module for a Short Circuit

1. Connect the "+" and "−" connections to the status control module.

2. Measure the resistance between terminal strip connections 5 and 1.

3. On engines that are equipped with a 70 pin connector, measure the resistance between terminals RM28 and RM1 in the EMCP II panel.

Expected Result:

The resistance is greater than 2 Ohms.

Results:

• OK - The resistance is greater than 2 Ohms. The status control module does not have a short circuit. Proceed to Test Step 7.

• Not OK - The resistance is less than 2 Ohms. The status control module has a short circuit.

  Repair: Replace the status control module. Verify that the original problem is resolved.

  STOP

Test Step 6. Check the Wiring for the EMCP II for a Short Circuit

1. Remove electrical power from the EMCP II panel.

2. Measure the resistance between terminals RM28 and RM1.

Expected Result:

The resistance is greater than 2 Ohms.

Results:

• OK - The resistance is greater than 2 Ohms. The wiring for the EMCP II does not have a short circuit. Proceed to Test Step 7.

• Not OK - The resistance is less than 2 Ohms. The wiring for the EMCP II has a short circuit.

  Repair: Repair the wiring or replace the wiring. Verify that the original problem is resolved.

  STOP

Test Step 7. Check the Harnesses for the Electronic Service Tool for a Short Circuit

1. Connect the harnesses for the electronic service tool to a service tool connector.

2. Measure the resistance between terminal strip connections 104 and 153.

Expected Result:

The resistance is greater than 2 Ohms.

Results:

• OK - The resistance is greater than 2 Ohms. The harnesses for the electronic service tool do not have a short circuit. Proceed to Test Step 8.

• Not OK - The resistance is less than 2 Ohms. At least one harness for the electronic service tool has a short circuit.

  Repair: Repair the harness for the electronic service tool. Replace parts, if necessary. Verify that the original problem is resolved.

  STOP

Test Step 8. Check the Electronic Service Tool for a Short Circuit

1. Connect the electronic service tool or a communications adapter to a service tool connector.

2. Measure the resistance between terminal strip connections 104 and 153.

Expected Result:

The resistance is greater than 2 Ohms.

Results:

• OK - The resistance is greater than 2 Ohms. The DDT or the communications adapter does not have a short circuit. Proceed to Test Step 8.

• Not OK - The resistance is less than 2 Ohms. The service tool or the communications adapter has a short circuit.

  Repair: Replace the faulty component. Verify that the original problem is resolved.

  STOP

Test Step 9. Check for a Voltage Drop

1. Verify that all of the connectors are connected.

2. Restore the electrical power to the engine.

3. Set the engine control to the STOP mode.

4. Measure the voltage across the power supply. Record the measurement.

5. Measure the voltage between terminals EISC-A and EISC-B. Record the measurement.

6. Measure the voltage between the + terminal and the − terminal of the status control module. Record the measurement.

7. Measure the voltage between terminals A and B for the harness for the electronic service tool.

Expected Result:

The voltage measurement at the power supply is at least 18 VDC. The voltage that is measured at each location is within two volts of the voltage that was measured at the power supply.

Results:

• OK - The power supply voltage is correct. The voltage drop across the wiring is within the specifications. The problem appears to be resolved.

  Repair: The initial problem was probably caused by a poor electrical connection. If you are troubleshooting an intermittent problem, refer to Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - The power supply voltage is incorrect or there is excessive voltage drop in the wiring.

  Repair: Identify the source of the low voltage. Repair the faulty component or replace parts, if necessary.

  STOP