Vehicle model: Huanghai Bus
Year: Oct., 2004
Engine type:ISC0268
VIN: LDD24E03840004329
Diagnostic principle and steps of imported Cummins ISC. In order to prevent short circuit and open circuit of engine communication line,this vehicle manufacturer designed 2 kind of diagnostic sockets:round 8-pin and Goods fonts 3-pin connector,which brings inconvenience to maintenance technician. The diagnostic procedure as below.

Diagnose with 9-pin diagnostic connector:
Find 9-pin diagnostic connector position of this vehicle;connect diagnostic socket,place ignition switch in ON position after confirm normal connection;Turn on power switch of Fcar car scanner. Check whether instrument fault light abnormal or not;Enter menu to select【Diesel】—【Cummins—【V5.8】—【Cummins diesel engine】—【Cummins ISC engine_24V】there are following functions:【Read DTC】—【Clear DTC—【Read data stream】

Use 3-pin diagnostic connector to diagnose:
Find 3-pin diagnostic position of this vehicle(See Pic.3),which located in nearby of computer board output line oil filter engine besides. To measure pin voltage with multimeter to confirm communication line;(Pin voltage see Table 1)use diagnostic line to connect with jumper box and main unit;
Connect with 3-pin diagnostic socket(See Pic.4)and jumper box pin(connection method of universal jumper box and diagnostic pin as shown in Table 2)
Due to 3-pin connector without peripheral device power supply, cigar lighter line or battery terminal line are required to supply power to peripheral device (namely scanner);
Note: Must use power supply on the same vehicle, ensuring above 12V, otherwise impact between voltages will result in failure to diagnose system.

Entry to menu to select【Diesel】—【Cummins】—【V5.8】—【Cummins diesel engine】—【Cummins ISC engine-24V】,there are following functions:【Read DTC】—【Clear DTC】—
【Read data stream】
Name Jumper box pin Diagnostic connector voltageV Diagnostic connector pin(See Pic.4) Function of Pin

Data stream name High speed Idle speed Static
OEM line plug supply voltage V 5.0 5.0 5.0
PTO state inactive inactive inactive
PTO set/recover switch Neutral gears Neutral gear Neutral gear
PTO additional switch Flameout Flameout Flameout
VCA degree 0.0 0.0 0.0
Drive ratio 48.9 16.0 0.00
Powertrain protection torque limit ftld 48335 48335 00000
Coolant temperature 68.9 66.7 66.7
engine oil pressure signal voltage V 1.0V 0.5V 0.0
engine cable supply voltage V 0.50 0.50 0.50
engine RPM 2315 650 0
engine speed sensor voltage V 5.0V 5.0V 5.0
Transmission drive ratio 0 0 0
Rear axle drive ratio switch Low Low Low
Injector control valve delay time ms 0.600 2.858 0.00
Injector control valve open time ms 0.600 2.858 0.00
Injection control valve circuit state normal normal normal
Cruise PTO switch flameout flameout flameout
Cruise control set/resume switch Neutral gear Neutral gear Neutral gear
Cruise control set/resume switch Neutral gear Neutral gear Neutral gear
Manual fan switch OFF OFF OFF

Maximum desired VCA degree 0.0 0.0 0.0 
Calibrated software state 0704C5E8 0704C5E8 0704C5E8
Accelerator signal voltage V 2.1 1.3 0.6
Accelerator state(Idle speed valid) Idle speed close Idle speed open Idle speed close
Accelerator supply voltage v 4.2 4.2 4.2
Throttle chain switch open open locked
Fuel pressure deviation psi o.2 o.1 o.o
Fuel moisture state No No No
Fuel temperature  35 36 30
Fuel economy mpg 0.31 .0..01 0.00
User fuel supply state open open engine stop
Fuel percentage % 0.00 0.00 0.00
Clutch switch release release release
Battery voltage V 26.7 24.7 24.7
Battery voltage psia 5002 5002 0.0
Accumulator pressure sensor voltage V 2.3 1.6 0.00
Accumulator pressure set point psa 5002 5002 0.0
Service brake switch release release depressed
Diagnostic switch flameout flameout flameout
Vehicle speed pmh 0 0 0
Intake manifold pressure KPa 54 60 101
Intake pressure signal voltage 4.04 3.04 0.0V
Intake manifold temperature  41 42 31
Intake manifold temperature signal voltage V 1.06 1.18 1.05
Remote PTO switch flameout flameout flameout
Remote accelerator pedal flameout flameout flameout
Intake heater flameout flameout flameout
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