Hummer H1 Service Manual page 1121

56 PCM/Tech 1 Scan Tool
DTC P0223 Accelerator Pedal Position (APP)
Sensor 2 Circuit High Voltage
Circuit Description
The Accelerator Pedal Position (APP) module provides a volt-
age signal that changes relative to accelerator position. There
are three sensors located within the APP module that are scaled
differently. This is a type C DTC.
Conditions for Setting the DTC
• Voltage is greater than 4.75 volts on APP 2.
• Conditions met for 2 seconds.
Action Taken When the DTC Sets
• The input from APP 2 sensor is ignored.
• A current and history DTC will set but it will not turn on
the "Service Throttle Soon" lamp. The throttle will op-
erate normally as long as there is only one malfunction
present. If two different APP sensors have a malfunc-
tion, the "Service Throttle Soon" lamp will light and the
PCM will limit power. If three APP sensors have a mal-
function present, the "Service Throttle Soon" lamp will
light and the PCM will only allow the engine to operate
at idle.
Conditions for Clearing the MIL/DTC
• 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
_____________________________________________________
ACCELERATIOR
PEDAL POSITION
SENSOR
44
D B
32
C
2
53
G A
17
F
1
60
E J
15
K
3
14
20
HOT IN RUN
22
AND START
C1
FUSE 3A
10 AMP
EXTERIOR
C5-A4
A
RESUME
ACCEL
HOT IN RUN
AND START
SET
COAST
FUSE 5C
10AMP
INTERIOR B
ON/
295 BR OFF
722 PP C29-A12
721 LB C27-C5
719 BR C29-B1
718 DB C29-B2
725 GY C27-D6
724 DG C27-D4
723 YL C27-D3
717 WH C27-D12
720 TN C28-C2
C5-D3
B
154 TN C28-D14
C
37
C27-D10
YL 153 LG
D
42
C29-B11
GRN 152 DB
A 29
RD 151 GY C29-A11
C1
temperature and engine coolant temperature exceeds
71°C (160°F) that same ignition cycle).
• Ignition must be cycled if P1125 is also set.
• Use of a Scan Tool
Diagnostic Aids
A scan tool reads APP 2 position in volts and should read about
4.5 volts with throttle closed and ignition "ON" or at idle. Volt-
age should decrease at a steady rate as throttle is moved toward
Wide Open Throttle (WOT). Also, 90% pedal travel is accept-
able for correct APP operation. Refer to Section 2 for "Inter-
mittents". Scan APP 2 signal while depressing accelerator
pedal with engine stopped and ignition "ON". Display should
vary from about 4.5 volts when throttle is closed to about 1.5
volts when throttle is held at Wide Open Throttle (WOT) posi-
tion. Its possible P1125 will set along with P0223 if the signal
circuit is open.
Test Description
Number(s) below refer to the number(s) on the diagnostic ta-
ble.
2. This step determines if P0223 is a hard failure or an intermit-
tent condition.
3. This step will check for an open in the ground circuit.
POWERTRAIN
CONTROL
MODULE
(PCM)
GROUND
APP 2
SIGNAL
GROUND
APP 1
SIGNAL
GROUND
APP 3
SIGNAL
5 VOLT
REFERENCE
WASTEGATE
SOLENOID
CONTROL
RESUME
ACCEL
SIGNAL
SET
COAST
SIGNAL
ON / OFF
SIGNAL
9-S12-055
®