Page 847 - Workshop Manual - Tunland (2017)

DIAGNOSTICS - ENGINE CONTROL SYSTEM 04-161

04
DTC inspection
DTC DTC definition Trouble location
conditions
ECU power output
• Battery
voltage 1 - data is
• Turbocharger
valid but below
P1938 actuator and its
normal operating harness
range - medium
• ECM
severity level.
ECU power output
• Turbocharger
voltage 1 - voltage is
actuator and its
P1939 above normal or harness
shorted to high • When the key • ECM
voltage power supply. switch is in ON
position, the
• Intake mass flow
diagnosis continues
ECU power output sensor and its
to run.
voltage 1 - voltage is harness
P1941 below normal or • Turbocharger
shorted to low voltage actuator and its
power supply harness
• ECM

Variable geometry • Turbocharger
turbocharger actuator actuator and its
P2198
drive circuit - root harness
cause unknown • ECM

Diagnosis Procedure
CAUTION

• To implement the following steps, ensure that ECM is grounded properly.
• Before conducting electric diagnosis, do refer to the reference circuit diagram
and the element information.
• Before conducting measurement, check the pins of connectors for rupture,
looseness and rust, and ensure that the pins are contacted properly.
• If the connection is good, check the sensor signal voltage when moving the
connector and harness. If a fault occurs, the voltage display on the diagnostic
instrument will change.

1 . DTC inspection
(a) Ignition switch: OFF.
(b) Connect the diagnostic apparatus.
(c) Use the diagnostic apparatus, read the fault code.
(d) Confirm whether there is fault code related to ECU power output voltage1?
Is the inspection result normal?

YES>To step 2.