FUSO engine fault light on

Model：FUSO
Year：June, 2007
 Chassis model：FV51JK
Engine type：6M70
VIN：JL6ERK6BX7K034727
Fault phenomenon：
　　Owner reflected that engine fault light of this vehicle is on(See Pic.1), meanwhile speedometer not work, Fuel consumption increase, speed limit meter always alarm overspending.
　　　Fault analysis：
    This vehicle is electronically controlled system, needs to use Fcar car scanner to diagnose and inspect, method as below:
1 First connect testing cable with OBD test head and main unit
2 Find diagnostic socket position of this vehicle (See picture 2)
3 Connect diagnostic socket and turn on ignition switch to ON
4 Turn on Fcar heavy duty scanner power switch
5 Enter menu and select【Diesel】——【FUSO】—【V5.1】——【Engine system】——【Read Fault code】——【5280  25 speed sensor】——【Clear fault code】——【Fault code clear success】——【Read fault code】——【5280  25 speed sensor】appears again，then means it’s true fault code。
                                                     
　Fault analysis and inspection：
　　　According to analysis of symptoms of this vehicle and fault code 【5280  25 speed sensor】,it is caused by vehicle speed sensor damage and line fault. Vehicle speed sensor is installed on nearby shell of output shaft for automatic transmission, ECU compute vehicle speed base on signal of vehicle speed sensor, and as the basis for shift control and remind owner of overspend driving.  
　　　Detection of sensor as below:
　　1. Vehicle inspection. Unplug vehicle speed sensor connector, to measure resistance between two terminals of sensor with multimeter,For different model of automatic transmission, resistance of vehicle speed sensor induction coil is different,  normally hundreds of Ohm to thousands of Ohm
　　Jack up vehicle, rotate impending drive wheel with hand, meanwhile to measure whether there is pulse induced voltage between two terminals of vehicle speed sensor. If pointer of multimeter swings, means sensor has output pulse voltage, sensor work normally; If not, means sensor malfunction, further inspection of sensor rotor and induced coil for dirty should be carried out. If dirty, please clean and test again. If sensor no pulse voltage, confirm that sensor has been damaged and needs to be replaced, vehicle speed sensor pulse voltage measurement(See picture 3)
　　2 Individual detection. Remove vehicle speed sensor, and measure sensor output pulse voltage. Specific operation is: Use a iron rod or a magnet to approach to or leave sensor rapidly, at the same time, to measure whether there is pulse voltage generated between two terminals of sensor with multimeter. If no induced voltage or induced voltage is very weak, means sensor is faulty, a further inspection should be carried out, and test again. Replace after confirm faulty.


　　　　　　　　　1 Park locking gear；2 Vehicle speed sensor; 3 Permanent magnet；4 Induction coil；5 Electronically controlled components

Troubleshooting：   
    No signal output of vehicle speed sensor is detected, replace vehicle speed sensor and test run on road. Fault light off, speedometer normal, trouble removed.　
B Engine data stream（FUSO、6M70）

Name of data stream	High speed	Idle	Static state
01  Engine speed rpm	1965	464	0
05  Fuel quantity℅	89.6	10.0	0
08  Actual fuel rail pressure ℅	68.9	25.0	0
09  Injection timing CA	3.1	0.0	0
0A  Pilot injection time CA	11.6	3.0	0
0B  Pilot injection amount mg/st	9.2	5.0	1.0
0D  Acceleration V	0.0	0.0	0.0
0E  Acceleration V	3.650	0.840	0.00
10  Vehicle speed km/h	0.0	0.0	0.0
11  Idle V	9.387	2.940	0.000
12  Water temperature °C	83.6	75.9	32.6
13  Fuel temperature °C	50.8	56.5	35.3
14  Air temperature °C	40.3	34.4	31
15  Q resistor	7	7	7
16  Air pressure kpa	110	100	100
17  Boos pressure kpa	320	100	000
18  Battery voltage V	28.60	28.20	24.6
23  PTO acceleration ℅	0.0	0.0	0.0
24  PTO acceleration V	3.650	0.840	0.00
25  PTO resisitor	1	1	1
35  ASC setting speed km/h	0.0	0.0	0.0

D Actuation test（FUSO、6M70）

• Light bulb ⊙red represents light on、⊙green represents light off，
• Engine speed read 530 represents Engine speed increase、Engine speed green 464 represents decrease/normal，
• Red √ represents works、Green×represents pause

Sensor name	Light（⊙symbol of bulb）		Engine speed rpm		Start √	Pause×
A6 Power retarder M/V-R	⊙		464
A7  Exhaust brake M/V	⊙		530	464	√	×
A8  Auxiliary brake S/L	⊙		464
A9  ASC light	⊙	⊙	464		√	×
AA  Auxiliary brake P/L	⊙		464
AB  DIAG light（R）	⊙	⊙	464		√	×
AC  DIAG light（U）	⊙	⊙	464		√	×
AD  A/C signal	⊙		568	464	√	×
AE Idle speed boost cancel	⊙		464
B2  Fuel leak check	⊙		464
B3  VGT test	⊙		464

Note: Actuation test must be performed under condition that control setting matching, sensor and line are confirmed normal, otherwise, it will leads to operation failure. If operation still failed in case of everything is normal for system, then means this vehicle not installed with actuation test system and no such function

3, Maintenance experience

　　　To perform vehicle engine system diagnosis and inspection, you must be familiar with usage of auto diagnostic tool and diagnostic methods and steps, such as check engine data stream, compare engine speed, high speed, idle speed, static state, working condition, so as to judge sensor is good or not.
　　　Actuation test is used for check control unit and parts whether work normal and also a method for Fcar vehicle scanner to judge the cause for fault.