Hummer H1 Service Manual page 1110

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DTC P0216 Injection Timing Control System
Circuit Description
Timing of the combustion event is accomplished by delivering
a pulse of fuel into the combustion chamber at a desired degree
of cylinder travel. This desired degree (defines the current po-
sition of the cylinder in relationship of Top Dead Center). This
test compares desired timing to measured timing when certain
conditions have been met. To retard injection timing the PCM
extends the stepper motor. To advance injection timing the
PCM retracts the stepper motor. This is a type B DTC.
Conditions for Setting the DTC
• Engine speed has not changed more than 56 rpm for
20.8 seconds.
• A 5 degree difference between Act. Inj. Time and Des.
Inj. Time.
Action Taken When the DTC Sets
Possible combustion noise.
Conditions for Clearing the MIL/DTC
• The PCM will turn the MIL off after three consecutive
trips without a fault condition.
• A History DTC will clear when forty consecutive
warm-up cycles that the diagnostic does not fail (coolant
temperature has risen 5°C (40°F) from start up
coolant temperature and engine coolant temperature ex-
ceeds 71°C (160°F) that same ignition cycle).
• Use of a Scan Tool.
05745159
A
5 VOLT
REFERENCE
PUMP CAM HIGH
SENSOR
SENSOR RESOLUTION
SIGNAL SIGNAL GROUND
B C D
C3 B8 C1
C5
C27-D14 C29-A4 C29-A2 C27-D9
5 VOLT CAM HIGH
REFERENCE SENSOR RES
SIGNAL SIGNAL
INJECTION TIMING
E STEPPEN MOTOR (ITS)
OPTICAL/ FUEL
TEMP SENSOR
F D A
C12 C2 A3 A2
C27-C8 A7 A8
C29
SENSOR FUEL TEMP ITS ITS
GROUND SIGNAL HI LO
Diagnostic Aids
A hard start and possible poor performance condition might
exist. Act. Inj. Time will freeze at the point of the fault. DTC
P0216 will set if injection timing is not set correctly. Refer to
Checking and Adjusting Injection Timing.
Test Description
Number(s) refer to the number(s) on the diagnostic table.
2. This step determines is a hard failure or an intermittent.
3. This step checks for an open or short in the injection timing
coil circuit 1.
4. This step checks for an open or short in the injection timing
coil circuit 2.
5. The important thing in this step is that the PCM is sending a
varying voltage (voltage may vary between 1 and 12 (usu-
ally you will see voltage vary between 5 and 6 when engine
is idling)), this will indicate that the PCM is OK and that
there is a problem with the injection timing stepper motor. If
there is a steady voltage present on any circuit, this will indi-
cate a problem with the PCM or a circuit shorted to voltage.
PCM/Tech 1 Scan Tool 45
M
B C
A6 A7
A9 A10
ITS ITS
POWERTRAIN
LO HI
CONTROL
POWERTRAIN
CONTROL
MODULE(PCM)
MODULE
9-S12-070