Page 975 - Workshop Manual - Tunland (2017)

DIAGNOSTICS - ENGINE CONTROL SYSTEM 04-289

DIAGNOSTIC TOOL CANNOT COMMUNICATE WITH THE ECU 04

Fault phenomenon Diagnosis logic Possible reasons
• ECU power supply circuit is
• CAN bus circuit
bad
he diagnostic tool cannot • ECU power supply circuit • Circuit breaks between
communicate with the ECU • ECM ground circuit
ECU and diagnosis tool
• ECM
• ECM

Diagnosis Procedure

1 . Check the motor data
(a) Ignition switch: OFF
(b) Connect the diagnosis tool with the fault diagnosis connector (16pins) on the lower
left of the dashboard.
(c) 点Ignition switch: Turn on the ignition switch, and start the diagnostic tool.
(d) Read the motor data shown on the diagnostic tool.

Check whether the data ow is normal or not.
YES>To step 2.
No >Maintenance related faults.

2 . Check other module data
(a) Read the ABS ( or other systems ) data shown on the diagnostic tool.
(b) Read the data shown on the diagnostic tool.

Can the diagnostic tool read the ABS ( or other systems ) module data ow ?
YES>To step 4.

No >To step 3.

3 . Check the communication CAN line of ECU
(a) Ignition switch: OFF.
(b) Disconnect the battery negative cable.
(c) Disconnect the ECU connector.
(d) Use a multimeter to measure and diagnose the continuity of interface connector C10
pin 6, 14 and ECU connector A24 pin 14 and 15.
(e) Use a multimeter to measure and diagnose the continuity of interface connector C10
pin 14, 6 and the grounding.
(f) Use a multimeter to measure and diagnose the resistance between the interface
connector C10 pin 14 and pin 6.

Standard resistance:

Connect the pin by pmultimeter Standard value
C10(6) - C99(44) Approx 0Ω

C10(14) - C99(45) Approx 0Ω