Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 4 of 4 Posts

·
Registered
2003 chevy trailblazer_ls
Joined
·
1 Posts
Discussion Starter · #1 ·
I have seen a lot of post about my problem but not sure how to pin point problem. I get the reduced engine power light. The engine seems to only go into reduced engine power when the gas is feathered. If I floor it and let off complety the light/engine runs normally, if I am use my cruse control it runs normally. But driving in town it reduces engine power. I have noticed latly that it trys to cut out more at cooler temps. The codes it is giving are - P1275, P1280, and P1271. I have replaced the pedal sensor twice and same problem. I need to know what to try next. One question I have, are there 2 sensors? I have replaced the pedal itself with the sensor attached. If there is another one could someone please tell me where it is located and where to purchase it.
 

·
Registered
2005 saab 9_7x
Joined
·
10 Posts
Hope this helps you out....

2003 Chevrolet TRAILBLAZER
Submodel: |Engine Type: L6|Liters: 4.2
Fuel Delivery: FI|Fuel: GAS


DTC Code: P1275

Description: Accelerator Pedal Position (APP) Sensor 1 Circuit
Probable Causes:

1- Sensor or solenoid faulty
2- Connector terminal contact is damaged or corroded
3- Wire harness - Check harness for correct voltage, open, short to ground or short to voltage
4- Update control unit software - Check for the latest control unit update
5- Powertrain or Engine Control Module faulty
 

·
Registered
2005 saab 9_7x
Joined
·
10 Posts
Subject: 02-05 Chevrolet, Buick, Oldsmobile and GMC Mid-Sized Utilities Reduced Power Light On and DTC P1680 P1221 and/or P1271 Stored in the PCM - kw fan clutch SES light power MIL 4.2 LL8 #PIT3138A - (11/01/2004)
Models: .

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:
Reduced power light on and DTC P1680 P1221 and/or P1271 stored in the PCM

Recommendation/Instructions:

Monitor the 5V reference to the Accelerator Pedal Position ( APP ) sensor, circuit 1274, using Peak Min/Max on a Fluke 87. Refer to Si document 1454678 for the 5V reference schematics. Command the fan clutch control "on" with the Tech 2 at 50%. If when commanding the fan clutch on, the 5V reverence spikes to battery voltage, the concern is the 5V reference shorted to battery voltage intermittently inside cooling fan clutch. Replace the fan clutch to repair this concern.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

Models:

(02 - 05 Chevrolet Trailblazer and Trailblazer EXT) and (02 - 05 GMC Envoy, Envoy XL and Envoy XUV ) and (02 - 05 Buick Rainier) and (02 - 04 Oldsmobile Bravada)
 

·
Registered
2005 saab 9_7x
Joined
·
10 Posts
Subject: Information on Normal APP and TP Signal Circuit 2 Voltage Fluctuation - keyword DTC low MIL P0122 P0123 P0220 P0222 P01120 P1220 P1221 P1271 P1275 P1280 P1512 P1514 P1515 P1523 P2101 P2120 P2122 P2123 #PIP3461 - (06/08/2005)


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

If the APP sensor 2 or TP sensor 2 signal circuit is monitored with an oscilloscope or Fluke 87 DVOM on the 1 ms min/max setting, it may be noted that the signal voltage decreases every 156 ms for 6.25 - 7.8 ms each time.

Recommendation/Instructions:

It is normal for these voltages to drop as described above. This is the result of the PCM testing the APP and TP sensors for internal shorts. During the PCM test for a DTC P2135 (P1221 on 02-03 Vue), the PCM shorts the TP sensor 2 signal to ground every 156 ms for 6.25 - 7.8 ms each time. During the PCM test for a DTC P2138 (P1271 on 02-03 Vue), the PCM shorts the APP sensor 2 signal to ground every 156 ms for 6.25 - 7.8 ms each time. At this time, the PCM monitors the APP sensor 1 and TP sensor 1 signal circuit voltages to ensure that they do not decrease with the sensor 2 signal circuits. If they do, an internal sensor short is present or the signal circuits are shorted together.

If there are no DTCs resetting but toggling voltages are encountered during inspection with an oscilloscope or Fluke 87 DVOM on the 1 ms min/max setting, no repairs should be attempted to prevent the voltages from toggling as it is a normal condition. If DTCs are resetting, follow the related SI diagnostic charts to diagnose the ETC system.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
 
1 - 4 of 4 Posts
Top