Signal functions include High Side Drive Outputs and Low Side Drive Return. For the Injector Drive Circuit (INJ) function diagram, see Figure
“Injector Drive Circuit Function Diagram”
.
Figure 1. Injector Drive Circuit Function Diagram
High Side Drive Outputs — The high side drive outputs control the individual injector on-time, injection timing and sequencing (firing order). The ECM controls each individual injector by providing current to each individual injector solenoid. Sufficient injection control pressure and a valid CMP signal must be received by the ECM before an injector will be allowed to fire.
Low Side Drive Return — The two low side drive circuits (one for cylinders 1, 2 and 3, one for 4, 5 and 6) provide a ground path for the injectors through the ECM and also allows the ECM to perform diagnostic measurements on injector performance.
Section 32.1.1
Fault Detection/Management
The ECM is capable of detecting, while the engine is running, individual injector circuit open and short conditions to either ground or power. If individual injector faults are detected while the engine is operating, the ECM can command an individual injector or a bank of injectors to turn off to enhance engine running and life, as well as provide a limp home capacity.
 |
| To avoid injury from unexpected engine startup, do not spray high-pressure water on the ECM. Stray voltage or a short in the circuitry may cause the ECM to malfunction. |
NOTICE: |
| Do not perform voltage checks with the engine running. The injector solenoid operating voltage, 115 volts DC @ 10 amps is present on the injector circuits |
A number of special On-Demand service bay tests can be commanded by the operator to verify injector circuit continuity as well as injector operation while the engine is operating in a test mode. For injector drive circuits (INJ), see Figure
“Injector Drive Circuits”
.
Figure 2. Injector Drive Circuits
Engine harness connector checks are listed in Table
“Engine Harness Connector Check to Chassis Ground”
. The checks are made through the connector with test pin, ignition key OFF.
| +Test Points- | Spec | Comments |
| 43 to Grd | > 1,000 Ω | Injector #1 high side power supply. |
| 21 to Grd | > 1,000 Ω | Injector #2 high side power supply. |
| 41 to Grd | > 1,000 Ω | Injector #3 high side power supply. |
| 42 to Grd | > 1,000 Ω | Low side voltage return injectors #1, #2, #3. |
| 46 to Grd | > 1,000 Ω | Injector #4 high side power supply. |
| 25 to Grd | > 1,000 Ω | Injector #5 high side power supply. |
| 44 to Grd | > 1,000 Ω | Injector #6 high side power supply. |
| 26 to Grd | > 1,000 Ω | Low side voltage return injectors #4, #5, #6. |
| If less than 1,000 Ω, check engine harness, under valve cover harness, and injector circuits for short to ground. | ||
The injector, under valve cover harness, engine harness circuit continuity checks are listed in Table
“Injector, Under Valve Cover Harness, Engine Harness — Circuit Continuity Check”
. The checks are made through the connector with test pin, ignition key OFF.
| +Test Points- | Spec | Comments |
| 43 to 42 | 3.4 ± 2 Ω | Injector circuit #1 |
| 21 to 42 | 3.4 ± 2 Ω | Injector circuit #2 |
| 41 to 42 | 3.4 ± 2 Ω | Injector circuit #3 |
| 46 to 26 | 3.4 ± 2 Ω | Injector circuit #4 |
| 25 to 26 | 3.4 ± 2 Ω | Injector circuit #5 |
| 44 to 26 | 3.4 ± 2 Ω | Injector circuit #6 |
| Resistance measured through complete injector circuit, including injector solenoid. If resistance is high or circuit is open, isolate problem to harness, connector or injector solenoid. | ||
Section 32.1.2
Function System Description
The Series 40E engine control system consists of a single ECM that provides the voltage and current required by the injectors to fuel the engine.
Fuel quantity, fuel rate and timing are all controlled by the single engine mounted ECM. The desired fuel and timing are calculated and controlled by the ECM from the input of various engine and vehicle sensors as well as the limits programmed into its internal memory.
Section 32.1.3
ECM Injector Diagnostics
The ECM monitors the voltage on each of the individual injector circuits, and is capable of detecting an open or shorted circuit. If the ECM detects a short to ground or a multiple fault in an injector circuit, it is capable of disabling an individual injector or a bank of three injectors, allowing the engine limp home capabilities on the remaining three cylinders. The Engine Warning Lamp will be illuminated when an injector circuit fault is present.
Note: The last digit of the flash code indicates the affected cylinder number. For example, Code 421 indicates cylinder No. 1 has an open circuit between the IDM high side driver and the low side (signal return) to the IDM. The SID numbers 1–6 indicate cylinder numbers in a similar manner.
Section 32.1.4
Flash Codes
The following Flash Codes could display when troubleshooting the injector drive circuits.
Section 32.1.4.1
Flash Codes 421 through 426
ATA Code SID 1 through 6 FMI 5
High side to low side open.
Flash codes for high side to low side open indicate an open circuit between the ECM high side driver and the low side (signal return) to the ECM.
The ECM will compensate for engine misfire to keep the engine operating. The ECM will not illuminate the engine warning light when this situation occurs.
Possible causes: Open wire in the injector harness; open injector return circuit or injector solenoid.
Section 32.1.4.2
Flash Codes 431 through 436
ATA Code SID 1 through 6 FMI 4
High side to low side short.
Flash codes for high side shorted to low side indicate the return voltage is too high due to a short circuit between the high side driver and return circuit.
The ECM will compensate for engine misfire to keep the engine operating. The ECM will not illuminate the engine warning light when this situation occurs.
Possible causes: Shorted injector solenoid or wiring harness.
Section 32.1.4.3
Flash Codes 451 through 456
ATA Code SID 1 through 6 FMI 6
High side shorted to ground or VBat.
Flash codes for high side shorted to ground or VBat indicate the return circuit shorted to ground.
If the ECM detects this fault, it will disable the entire bank of cylinders associated with the cylinder indicated. The ECM will not illuminate the engine warning lamp when this occurs.
Possible causes: Shorted injector solenoid or wiring harness to ground.
Section 32.1.4.4
Flash Code 513
ATA Code SID 151 FMI 5
Low side to Bank 1 open.
With the low side to Bank 1 open, the ECM has detected an open circuit to the injectors on the cylinders 1 through 3.
With Flash Code 513 active, the drivers for cylinders 1 through 3 are inoperative. The ECM will compensate for misfire to keep the engine operating and will illuminate the engine warning light.
Section 32.1.4.5
Flash Code 514
ATA Code SID 151 FMI 5
Low side to Bank 2 open.
With the low side to Bank 2 open, the ECM has detected an open circuit to the injectors on cylinders 4 through 6.
With Flash Code 514 active, the drivers for cylinders 4 through 6 are inoperative. The ECM will compensate for misfire to keep the engine operating and will illuminate the engine warning light.
Section 32.1.4.6
Flash Code 515
ATA Code SID 151 FMI 6
Bank 1 low side short to ground or B+.
Flash Code 515 indicates the ECM has detected the low side driver for cylinders 1 through 3 has excessive current draw.
With Flash Code 515 active, the driver for cylinders 1 through 3 will be disabled. The ECM will compensate for engine misfire to keep the engine running. This code will cause the engine warning light to illuminate.
Section 32.1.4.7
Flash Code 521
ATA Code SID 152 FMI 6
Bank 2 low side short to ground or B+.
Flash Code 521 indicates the ECM has detected excessive current draw on the low side driver for cylinders 4 through 6.
With Flash Code 521 active, the driver for cylinders 4 through 6 will be disabled. The ECM will compensate for engine misfire to keep the engine operating and will illuminate the engine warning light.
| Series 40E Troubleshooting Manual – 6SE241 |
| Generated on 10-13-2008 |