Car keeps going into reduced power mode

Tiny
CBOSWELL
  • MEMBER
  • 2005 CHEVROLET UPLANDER
  • 211,160 MILES
Its giving codes 2135 1125 2101 2120 2138 Any suggestions on how to pinpoint the culprit would be greatly appreciated
Do you
have the same problem?
Yes
No
Thursday, January 19th, 2012 AT 10:36 PM

3 Replies

Tiny
RIVERMIKERAT
  • MEMBER
P2135= TPS 1-2 correlation.
P2101=Control Module Throttle Actuator Performance.
P2120=Accelerator Pedal Sensor Circuit 1.
P2138=Accelerator Pedal Position Sensor 1-2 Correlation.
P1125=Accelerator Pedal Position Sensor System.
ENGINE CONTROLS - 3.5L - DTC P0446 TO P1404 -2005 Chevrolet Uplander
Page 1 of 2
DTC P1125

Circuit Description

The accelerator pedal position (APP) sensor 1 and APP sensor 2 are potentiometer type sensors, each with the following circuits:
? A 5-volt reference circuit ? A low reference circuit
? A signal circuit
The control module provides the APP sensors a 5-volt reference circuit and a low reference circuit. The APP sensors then provide the control module signal voltages proportional to pedal movement. The APP
sensor 1 signal voltage is low at rest and increases as the pedal is depressed. The APP sensor 2 signal voltage is also low at rest and increases as the pedal is depressed. One APP sensor DTC will not cause
the Reduced Engine Power message to be displayed. Two APP sensor DTCs for the same sensor also will not cause the Reduced Engine Power message to be displayed. However, if two or more DTCs are
set involving more than one APP sensor, DTC P1125 will set.
DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P1125 Accelerator Pedal Position (APP) System
Conditions for Running the DTC

? DTCs P0606, P2108, U0107 are not set. ? The ignition is ON.
? The communications between the throttle actuator control (TAC) module and the powertrain control module (PCM) must be valid.
Conditions for Setting the DTC

Two APP sensors are out of range, or both APP sensors disagree with each other.
Action Taken When the DTC Sets

? The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
? The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
? The control module commands the TAC system to operate in the Reduced Engine Power mode. ? A message center or an indicator displays Reduced Engine Power.
? Under certain conditions the control module commands the engine OFF.

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0446 TO P1404 -2005 Chevrolet Uplander
Page 2 of 2
Conditions for Clearing the MIL/DTC

? The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
? A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
? A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
? Clear the MIL and the DTC with a scan tool.
Test Description

The number below refers to the number on the diagnostic table.
2: When the conditions that caused the APP sensor DTCs to set are corrected, the status of this DTC will change to History.
DTC P1125 Step
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Powertrain Control Module (PCM) Connector End Views
Did you perform the Diagnostic System Check - Vehicle?
Action
Yes
No
Go to Diagnostic System Check -
Vehicle in Vehicle DTC Information
1
Go to Step 2
This DTC indicates that 2 or more accelerator pedal position (APP) sensor DTCs are also set.
Refer to the APP sensor DTCs that are set and perform those diagnostic tables.
Does the scan tool display any DTCs that you have not diagnosed?
Go to Diagnostic Trouble Code
(DTC) List - Vehicle in Vehicle
DTC Information
2
System OK

ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 1 of 3
DTC P2101

Circuit Description

The commanded throttle position, based on the accelerator pedal position (APP), is compared to the actual throttle position. The throttle position values should be within a calibrated range of each other.
The throttle actuator control (TAC) module monitors the commanded and actual throttle position. If the TAC module detects that the commanded and the actual throttle positions are not within a calibrated
range of each other, a message is sent to the powertrain control module (PCM) across serial data, and DTC P2101 is set.
DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P2101 Control Module Throttle Actuator Position Performance
Conditions for Running the DTC

? The ignition is in the Crank or Run position. ? The system is not in Battery Saver mode.
? The ignition voltage is more than 5.23 volts.
? The communication between the TAC module and the PCM must be valid.
Conditions for Setting the DTC

? The TAC module detects that the commanded and the actual throttle positions are not within a calibrated range of each other.
OR
? The TAC module or the PCM cannot determine throttle position.
Action Taken When the DTC Sets

? The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
? The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
? The control module commands the TAC system to operate in the Reduced Engine Power mode. ? A message center or an indicator displays Reduced Engine Power.
? Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 2 of 3
? The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
? A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
? A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
? Clear the MIL and the DTC with a scan tool.
Diagnostic Aids

? Inspect for mechanical conditions or for binding that may be temperature related. Components may not move freely in extreme heat or cold due to the presence of contaminants or ice formation.
? If the condition is intermittent, refer to Intermittent Conditions.
DTC P2101 Step
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views and Engine Controls Connector End Views
Did you perform the Diagnostic System Check - Vehicle?
Action
Values
Yes
No
Go to Diagnostic
System
Check
Vehicle in Vehicle DTC
Go to Step 2 Information Go to
Diagnostic Trouble
Code (DTC) List - Vehicle
in Vehicle DTC
Information Go to
Diagnostic Trouble
Code (DTC) List - Vehicle
in Vehicle DTC
Information
-

1
-
Is DTC P2108 also set?
2
-
Go to Step 3
Is DTC U0107 also set?
3
-
Go to Step 4
1. 2.
Turn OFF the ignition for 15 seconds. Turn ON the ignition, with the engine
OFF.
3. Observe the TP sensor 1 and TP sensor 2 angle parameter with a scan tool.
Slowly depress the accelerator pedal to
4.

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 3 of 3
wide open throttle (WOT) and then slowly return the pedal to closed
throttle.
4
100%
Does the throttle position (TP) sensor 1 and TP sensor 2 angle increase to near the specified
value as the pedal is depressed and decrease as the pedal is released?
Test the electronic throttle control (ETC) ignition 1 voltage circuit for high resistance.
Refer to Circuit Testing in Wiring Systems.
Did you find and correct the condition? Replace the throttle body assembly. Refer to
Throttle Body Assembly Replacement. Did you complete the replacement?
Go to Diagnostic
Aids
Go to Step 5
andWiring Repairs
5

-
Go to Step 7
Go to Step 6
6
-
Go to Step 7
-
1. 2. 3. 4.
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds. Start the engine.
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.
7
-
Go to Step 2 Go to
Diagnostic Trouble
Code (DTC) List - Vehicle
in Vehicle DTC
Information
Go to Step 8
Did the DTC fail this ignition? IMPORTANT:
Be aware that repairing one individual condition may correct more than one DTC.
8
-
Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?
System OK

ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 1 of 5
DTC P2120

Circuit Description

The accelerator pedal position (APP) sensor 1 is a potentiometer type sensor with the following three circuits:
? A 5-volt reference circuit ? A low reference circuit
? A signal circuit
The control module provides the APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensor then provides the control module a signal voltage proportional to pedal movement. The APP
sensor 1 signal voltage is low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 1 signal or the APP sensor 5-volt reference voltage is outside the
predetermined range, DTC P2120 sets.
DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P2120 Accelerator Pedal Position (APP) Sensor 1 Circuit
Conditions for Running the DTC

? DTC P2107 is not set. ? The ignition is ON.
? The ignition voltage is more than 5.23 volts.
Conditions for Setting the DTC

? The APP sensor 1 voltage is less than 0.235 volt or more than 4.487 volts.
OR
? The APP sensor 2 5-volt reference voltage is less than 4.54 volts or more than 5.21 volts.
Action Taken When the DTC Sets

? The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
? The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
? The control module commands the TAC system to operate in the Reduced Engine Power mode. ? A message center or an indicator displays Reduced Engine Power.

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 2 of 5
? Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the DTC

? A current DTC Last Test Failed clears when the diagnostic runs and passes.
? A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
? Clear the DTC with a scan tool.
DTC P2120 Step
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views and Engine Controls Connector End Views
Did you perform the Diagnostic System Check - Vehicle?
Action
Values
Yes
No
Go to Diagnostic
System Check - Vehicle in
Vehicle DTC Information
1
-
Go to Step 2
1.
Turn ON the ignition, with the engine OFF.
Observe the accelerated pedal position (APP) sensor 1 voltage with the
accelerator pedal in the rest position with a scan tool.
2.
2
0.24-2 V
Go to Step 4
Go to Step 3
Is the voltage within the specified range?
1. 2. 3.
Turn OFF the ignition.
Disconnect the APP harness connector. Turn ON the ignition, with the engine
OFF.
Measure the voltage of the APP sensor 1 5-volt reference circuit with a DMM.
3
4.6-5.2 V
4.
Go to Step 6 Go to
Diagnostic Trouble
Code (DTC) List - Vehicle
in Vehicle DTC
Information
Go to Step 9
Is the voltage within the specified range? Is DTC P2138 also set?
4
-
Go to Step 5
1.
Observe the Freeze Frame/Failure Records for this DTC.

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 3 of 5
2. 3. 4.
Turn OFF the ignition for 30 seconds. Start the engine.
Operate the vehicle within the Conditions for Running the DTC as
specified in the supporting text or as close to the Freeze Frame/Failure
Records that you observed.
5
-
Go to Intermittent
Conditions
Go to Step 6
Did the DTC fail this ignition?
1. 2.
Turn OFF the ignition. Disconnect the accelerator pedal
harness connector.
3. Turn ON the ignition, with the engine OFF.
Observe the APP sensor 1 voltage parameter with a scan tool.
6
0 V
4.
Go to Step 7
Go to Step 11
Is the voltage at the specified value?
1.
Connect a fused jumper wire between the APP sensor 1 5-volt reference
circuit and the APP sensor 1 signal circuit at the accelerator pedal harness
connector.
Observe the APP sensor 1 voltage parameter with a scan tool.
7
4.6-5.2 V
2.
Go to Step 13
Go to Step 8
Is the voltage within the specified value?
1. 2. 3.
Turn OFF the ignition. Remove the fused jumper.
Turn ON the ignition, with the engine OFF.
Measure the voltage of the APP sensor 5-volt reference circuit with a DMM.
8
4.6-5.2 V
4.
Go to Step 10
Go to Step 9
Is the voltage within the specified range? Does the DMM indicate voltage less than the
specified value on the APP sensor 1 5-volt reference circuit?
Test the APP sensor 1 signal circuit for an open or for high resistance. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Test the APP sensor 1 signal circuit for a short to voltage. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
9
5 V
Go to Step 14 Go to Step 16
10
-
Go to Step 22 Go to Step 12
11
-

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 4 of 5
Go to Step 22
Go to Step 19
Did you find and correct the condition?
Test the APP sensor 1 signal circuit for a short to ground. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems. Did you find and correct the condition?
Test the APP sensor 1 low reference circuit for an open or for high resistance. Refer to
Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Test the APP sensor 1 5-volt reference circuit for an open or for high resistance. Refer to
Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Test the APP sensor 1 5-volt reference circuit for a short to ground. Refer to Circuit Testing
and Wiring Repairs in Wiring Systems. Did you find and correct the condition?
Test the APP sensor 1 5-volt reference circuit for a short to voltage. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition? Is DTC U0107 also set?
12
-
Go to Step 22 Go to Step 19
13
-
Go to Step 22 Go to Step 17
14
-
Go to Step 22 Go to Step 15
15
-
Go to Step 22 Go to Step 19
16
-
Go to Step 22 Go to Step 19 Go to
Diagnostic Trouble
Code (DTC) List - Vehicle
in Vehicle DTC
Information
17
-
Go to Step 18
Test for an intermittent and for a poor connection at the accelerator pedal harness
connector. Refer to Testing for Intermittent Conditions and Poor Connections and
Connector Repairs in Wiring Systems. Did you find and correct the condition?
Test for an intermittent and for a poor connection at the throttle body harness
connector. Refer to Testing for Intermittent Conditions and Poor Connections and
Connector Repairs in Wiring Systems. Did you find and correct the condition?
Replace the accelerator pedal assembly. Refer to Accelerator Controls Pedal
Replacement.
Did you complete the replacement?
Replace the throttle body. Refer to Throttle
18
-
Go to Step 22 Go to Step 20
19
-
Go to Step 22 Go to Step 21
20
-
Go to Step 22
-

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 5 of 5
Body Assembly Replacement. Did you complete the replacement?
21
-
Go to Step 22
-
1. 2. 3. 4.
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds. Start the engine.
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.
22
-
Go to Step 2 Go to
Diagnostic Trouble
Code (DTC) List - Vehicle
in Vehicle DTC
Information
Go to Step 23
Did the DTC fail this ignition? IMPORTANT:
Be aware that repairing one individual
condition may correct more than one DTC.
23
-
Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?
System OK

ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 1 of 3
DTC P2135

Circuit Description

The throttle body assembly contains the following components:
? The throttle blade
? The throttle actuator motor
? The throttle position (TP) sensor 1 and TP sensor 2 ? The throttle actuator control (TAC) module
The TAC system monitors the throttle position with 2 sensors. If the powertrain control module (PCM) receives a message from the TAC module that the throttle position, as indicated from TP sensor 1,
disagrees with the throttle position indicated from TP sensor 2, DTC P2135 will set.
DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P2135 Throttle Position (TP) Sensor 1-2 Correlation
Conditions for Running the DTC

? DTC P0606, P2108, U0107 are not set.
? The ignition switch is in the Crank or Run position. ? The ignition voltage is more than 5.23 volts.
? The communication between the TAC module and the PCM must be valid.
Conditions for Setting the DTC

? The throttle position indicated by TP sensor 1 disagrees with the throttle position indicated by TP sensor 2 by more than 6 percent.
OR
? The PCM learned minimum throttle position of TP sensor 1 disagrees with the learned minimum throttle position of TP sensor 2.
OR
? The PCM detects that the TP sensor 1 signal circuit is shorted to the TP sensor 2 signal circuit.
Action Taken When the DTC Sets

? The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 2 of 3
and fails.
? The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
? The control module commands the TAC system to operate in the Reduced Engine Power mode. ? A message center or an indicator displays Reduced Engine Power.
? Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC

? The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
? A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
? A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
? Clear the MIL and the DTC with a scan tool.
DTC P2135 Step
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views and Engine Controls Connector End Views
Did you perform the Diagnostic System Check - Vehicle?
Action
Yes
No
Go to Diagnostic System Check -
Vehicle in Vehicle DTC Information
1
Go to Step 2
Go to
Trouble Code
(DTC) List
Vehicle in Vehicle DTC Information
Diagnostic
Are any other DTCs set?
-

2
Go to Step 3
Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement.
Did you complete the replacement?
3
Go to Step 4
-
1. 2. 3.
4.
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds. Start the engine.
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.
4
Go to Step 2
Go to Step 5
Did the DTC fail this ignition? IMPORTANT:
Be aware that repairing 1 individual condition
may correct more than 1 DTC.
Go to Diagnostic

1/19/2012
ENGINE CONTROLS - 3.5L - DTC P0138 TO U0107 -2005 Chevrolet Uplander
Page 3 of 3
Trouble Code
(DTC) List
Vehicle in Vehicle DTC Information
Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?
-
5
System OK
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Thursday, January 19th, 2012 AT 11:07 PM
Tiny
CBOSWELL
  • MEMBER
Should there be any play in the throttle body?
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answer
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Friday, January 20th, 2012 AT 4:43 PM
Tiny
RIVERMIKERAT
  • MEMBER
No. That will cause a vacuum leak.
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answer
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Friday, January 20th, 2012 AT 10:14 PM

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