DTC P1104 (LDD)
Diagnostic Instructions
DTC Descriptor
| DTC P1104 00: Throttle Actuator Control (TAC)
Motor Control Circuit Shorted |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Motor Control 1
|
P1516 00, P2101 00, P2176 00
|
P1516 00, P2101 00, P2176 00
|
P1516 00, P2101 00, P2176 00
|
P1516 00, P2101 00, P2176 00, P1104 00
|
Motor Control 2
|
P1516 00, P2101 00, P2176 00
|
P1516 00, P2101 00, P2176 00
|
P1516 00, P2101 00, P2176 00
|
P1516 00, P2101 00, P2176 00, P1104 00
|
|
| |
Circuit/System Description
The engine control module (ECM) is the control center for the
throttle body throttle actuator control (TAC) system. The ECM
determines the drivers intent and then calculates the appropriate
throttle response. The ECM achieves throttle positioning by
providing a pulse width modulated voltage to the throttle body
(TAC) motor. The throttle body (TAC) motor system uses the
following circuits:
| • |
Throttle body (TAC) motor
control 1 |
| • |
Throttle body (TAC) motor
control 2 |
Two processors are also used to monitor the throttle body (TAC)
motor system data. Both processors are located within the ECM. Both
processors monitor each others data to verify that the indicated
throttle position is correct.
Conditions for Running the DTC
| • |
The ignition is ON or the
engine is operating. |
| • |
The ignition voltage is
greater than 7 V. |
| • |
The system is not in battery
safe mode. |
| • |
DTC P0068 00 is not
set. |
| • |
DTCs P1516 00 and P2101 00 run
continuously once the above conditions are met for greater than 5
s. |
Conditions for Setting the DTC
The indicated throttle position does not match the predicted
throttle position for more than 0.5 s.
Action Taken When the DTC Sets
DTCs P1104 00 is a Type B DTC.
Conditions for Clearing the DTC
DTCs P1104 00 is a Type B DTC.
Diagnostic Aids
| • |
A high resistance condition
with the throttle position sensor circuits may cause DTCs P1516 00,
P2101 00, P2119 00, or P2176 00 to set. |
| • |
Inspect for a condition in
which the throttle valve may have been held open. For example, ice
may have formed in the throttle bore causing the throttle valve not
to close. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Ignition ON, engine OFF, use a
scan tool to observe the throttle position sensor 1 indicated
position. Throttle position should increase as pedal is applied and
decrease as pedal is released. When no accelerator pedal activity
is detected, the throttle position will return to the spring loaded
default position. |
|
Note: A low voltage
condition may set this DTC.
|
| 2. |
Review the freeze
frame/failure records and ensure sufficient ignition voltage was
present when the DTC was set. |
| ⇒ |
If voltage was low, verify with the owner that the
battery was not discharged. If the battery has not been discharged,
refer to
Power Mode Mismatch . |
| 3. |
Operate the vehicle within the
conditions for running the DTC. You may also operate the vehicle
within the conditions that you observed from the freeze
frame/failure records data. |
Circuit/System Testing
| 1. |
Inspect the Q38 Throttle Body
for the following conditions: |
| |
• |
A throttle blade that is not
in the rest position |
| |
• |
A throttle valve that is
binding open or closed |
| |
• |
A throttle valve that opens or
closes without spring pressure |
| ⇒ |
If a condition is found, replace the Q38 Throttle
Body. |
|
Note: Disconnecting
the throttle body harness connector causes additional DTCs to
set.
|
| 2. |
Ignition OFF, disconnect the
harness connector of the Q38 Throttle Body. |
| 3. |
Ignition ON, test for greater
than 9 V on the Q38 Throttle Body motor control 1 circuit terminal
A and Q38 Throttle Body motor control 2 circuit terminal B.
|
| ⇒ |
If less than the specified range, test the
appropriate Q38 Throttle Body motor control circuit for a short to
ground, or an open/high resistance. If the circuit tests normal,
replace the K20 Engine Control Module. |
| 4. |
Ignition ON, probe the Q38
Throttle Body motor control 1 circuit terminal A and Q38 Throttle
Body motor control 2 circuit terminal B with a test lamp connected
to ground. Verify the test lamp does not illuminate. |
| ⇒ |
If the test lamp illuminates, test the appropriate
Q38 Throttle Body motor control circuit for a short to voltage. If
the circuit tests normal, replace the K20 Engine Control
Module. |
| 5. |
Set the DMM to Alternating
Current (AC) hz on the 400 mV scale. Engine idling, test for
greater than 2000 AC hz between the Q38 Throttle Body motor control
circuits listed below and ground while commanding the Engine Speed
to 1 950 RPM with a scan tool. |
| |
• |
Motor control 1 circuit
terminal A |
| |
• |
Motor control 2 circuit
terminal B |
| ⇒ |
If less than the specified value, replace the K20 Engine
Control Module. |
| 6. |
If all circuits test normal,
replace the Q38 Throttle Body. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
