Modern automotive dash panel and a display information processing has become the center of the entire vehicle, which vehicle data transmission via the network to each control unit, on the one hand the operation of the vehicle monitoring information displayed to the driver in real time by priority, to ensure traffic safety and driving comfort; on the other hand can also play the role of in-vehicle fault diagnostic, ready to detect the system, and through it to personalize the vehicle. The following is a composition Cayenne instrument fault diagnosis instance.
Failure phenomenon: a 2003 annual Porsche Cayenne SUV, equipped with a V8 4.5 L engine, mileage 118 000 km. Users reflect the instrument alarm, suggesting check generator.
Check Analysis: ignition switch open, instrument display ldquo; Start Enginerdquo ;, which indicates the battery power is low. Start the engine, there ldquo; Start Enginerdquo; prompt, then the meter displays voltage is 11.8 V, indicate that the battery is not currently charged. Measured with a multimeter external power left engine column voltage is 13.8 ~ 14.2V, the generator is working properly described. Detected by a dedicated fault diagnostic Porsche PIWIS Tester (FIG. 1), and found that there are many in the plurality of control units fault code, the fault code as follows.
FIG 1
(1) the presence of the instrument cluster control unit fault code has: 0455mdash; mdash; Kessy control unit (comfort CAN), 0457 mdash; mdash; vehicle electrical system control unit (comfort CAN), 1320mdash; mdash; air-conditioning system control unit, 1327mdash; mdash; parking assist control means, 1331mdash; mdash; driver side door control unit, 1332mdash; mdash; front passenger door control unit, 1333mdash; mdash; left rear door control unit, 1334mdash; mdash; rear right door control unit, 0470mdash; mdash; singlet operation comfort CAN, 0469 mdash; mdash; informationEntertainment CAN (singlet operation), 1305mdash; mdash; infotainment CAN and 0908mdash; mdash; wiper motor (with control unit).
(2) the presence of a gateway control unit has fault code: 1330mdash; mdash; rear control unit facilities, 0484mdash; mdash; a magnetic field sensor (compass) a control unit, 0459 mdash; mdash; PCM 2 and 0466mdash ; mdash; column switch (having an electrical means).
(3) the presence of an engine control unit with a fault code DME: P0564mdash; mdash; A cruise control multifunctional input circuit, P1608mdash; mdash; CAN cruise control, P1610mdash; mdash; CAN timeout (air conditioning), P0074mdash ; mdash; ambient temperature sensor, P1610mdash; mdash; CAN timeout (instrument cluster), P1613mdash; mdash; CAN (vehicle electrical system control unit) and P1614mdash; mdash; CAN timeout (steering angle sensor).
(4) of the vehicle body electrical system control unit has a fault code is present: 0907mdash; mdash; vehicle electrical system / DME load management operation and 1336mdash; mdash; comfort CAN closed.
After clear the fault is detected again found, the gateway control unit and DME no fault code storage. Instrument cluster control unit there are two faults do, namely: 0470mdash; mdash; singlet operation comfort CAN, the open circuit fault type; 0469mdash; mdash; infotainment CAN, single line operation, open circuit fault type, fault both memory is currently exist. The presence of a vehicle electrical system control unit fault code: 0907mdash; mdash; vehicle electrical system / DME load management operation after fault (fault code requires that each vehicle in the case where the system is functioning properly, and DME system for electrical load to clear the adaptive function ).
ClearAfter fault memory, fault code and the rest of this failure are not directly related, the need for in-depth examination. Porsche PIWIS information system into the vehicle in PPN LAN, query vehicle maintenance records. The car was found and repaired off intermittent faults can not start the engine, and the control unit replace the DME. The reason for the fault line corrosion, this time from the maintenance intervals for six months. Thus speculated that this fault line should remain with the problem.
starting the engine, the control unit into the instrument cluster with PIWIS Tester, display power supply voltage is 11.8 V. DME into the control unit, the display engine speed is 920 r / min, the supply voltage is 13.9 V. Entering vehicle electrical system control unit, a display supply voltage is 13.9 V. Thus the power control unit of the combination instrument in question.
The inspection focused on the instrument cluster, on the observed time meter display inconsistent with the actual time. 00:20 instrument display, and the time was 09:28 in the morning, indicating that the time had just been cleared to zero. Without human adjustment, the instrument system which may be caused by the power interruption, the instrument itself may be faulty. Just then, the Real found that the combination meter, parking assist indicator, air conditioning control panel flicker of a turn on and off, and accompanied by the sound of relay and adjust the motor continues to work. At this time, a combination meter inaccessible PIWIS Tester (FIG. 2), a gateway, DME and the vehicle electrical system control unit.
FIG. 2
off the ignition switch, to start the vehicle again, the fault disappears. Into the instrument cluster with PIWIS Tester again, gateways, DME and the vehicle electrical system control unit, in addition to 0907, the other fault code can be cleared. The last 0470,0469 fault code does not clear, indicating that the system unstable. Sometimes no
In order to reproduce the failure, I frequent starting of the vehicle, found malfunction. When the multifunction display flashes, voltage swing table, and each indicator on the meter, tachometer, fuel gauge, and the oil temperature are all normal. By this time the fault point has been determined in the initial part of the power supply of the instrument cluster, decided to check the ignition switch output line 15 is normal. Enter Kessy with PIWIS TesterThe control unit reads the actual value of the ignition switch position, when the ignition switch is displayed ldquo first speed; 0rdquo ;, ldquo displayed at the second speed; 1rdquo ;. In block 2 the ignition switch, not the car, measured with a multimeter instrument cluster fuse F26, F40 voltage is 13.6V (external charger). After repeated switching test found no blackouts, exclude the possibility of such an ignition switch and circuit failure.
Figure 3
disconnect the battery, remove the combination instrument, unplugging (FIG. 3), check the power supply and grounding lines. Measured with a multimeter, the fuse 26 (FIG. 4) to the power supply terminal of the resistor A1 is 0.6 Omega;, fuse 40 to the power supply terminal of the resistor A8 and A23 for 0.5 Omega;, line 15 and line 30, the insulation good, A9 and A24 of the ground terminal ground resistance of 375 Omega ;, measured as 34.5 ~ 41.8 Omega again ;. Ground fault point described in this line.
Figure 4
Figure 5
Troubleshooting: find information that grounding point as MB23, in the driver’s side of the instrument table (FIG. 5). Checked that the grounding point fixing nut loose, the grounding line is virtual connection state. Ground nut rear fastening point, refitted combination instrument, start the vehicle, the instrument cluster displays all normal, the voltmeter indicated as 14V. After the operation of the engine 15 min, for vehicle electrical system control unit and the control unit DME load adaptation function, a fault code 0907 may be cleared. At this point fault completely ruled out.
Review Summary: For fail because the line was bad cause, diagnosis, emphasis should be placed on the failure to reproduce. Before the failure to grasp the law, do not go alone diagnostic trouble codes, it is easy to go astray. In the present embodiment has a fault code failure: 0470,0469 and 0907. If you go around these fault codes for troubleshooting system CAN network, presumably there will be many twists and turns. I will fault code aside, first try to make the failure to reproduce, and observed in the process many of the useful Symptom diagnosis. Through the analysis of these symptoms are, The point of failure will soon be locked in a power supply portion of the instrument cluster, seemingly complicated fault be resolved quickly.
(LI)