Component Location
General Description
Several control units are applied to vehicle accordign to the increasing tendancy of electronically controlled vehicle. These units perform each control with informations from various sensors. Sharing informations from sensors and another parts is needed, so CAN communication type whose communication speed is high with insensitivity to electrical outer noise by spark generation is adopted to controlling power-train(engine, atutomatic transaxle, ABS, TCS, ECS).
As sharing signals of engine speed, APS, current gear recognition and torque reduction through CAN communication, ECM, TCM, ESP, TCS, ABS and 4WD modules perform active controls.
DTC Description
P1603 is set when signal communication through CAN line is not detected for more than 1 sec. This code is due to the poor connection of CAN communication line and CAN controller problem of communication module such as ECM,TCM,ESP,ABS,4WD.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | ? Signal monitoring | ? CAN communication line circuit ? CAN communication unit component |
Enable Conditions | ? Ignition "ON" |
Threshold Value | ? When communication through CAN line is not detected |
Diagnostic Time | ? 1.0s |
Fail Safe | Fuel Cut | NO |
EGR Off | NO |
Fuel Limit | NO |
MIL | NO |
Specification
Communication Format | DIGITAL "0" | DIGITAL "1"( BUS IDLE ) | CAN Communication Line Resistance |
CAN 2.0B | HIGH | LOW | HIGH | LOW | Inside of ECM | Inside of TCM |
3.5V | 1.5V | 2.5V | 2.5V | 120? (20?) | 120? (20?) |
Schematic Diagram
Schematic Diagram
Signal Waveform
Monitoring CAN HIGH and LOW simultaneously is important in monitoring CAN communication waveform. When CAN HIGH signal rise to 3.5V and LOW signal drops to 1.5V - voltage difference between HIGH and LOW signal is 2V - at BUS IDLE state(DIGITAL "1") whose reference voltage is 2.5V, "0" is recognized. Besides, comparing HIGH and LOW signal if opposite waveform is detected with the reference voltage of 2.5V, Check if current CAM signal is transfers correctly.
Continuous "0"signal above 6BIT means the occurence of error in CAN communication. 1BIT is easily distinguished as calculating the time when "SOF"(START OF FRAME) which notifies the start of frame occurs. Check if "0"signal above 6BIT is detected continuously when monitoring CAN communication waveform.