NHTSA ID Number: 10111705
Manufacturer Communication Number: PIP4912E
Summary
This Preliminary Information communication provides information to the technician on vehicles that may have an intermittent high idle. If a technician has duplicated, or the customer description aligns with the speeds mentioned in the idle speed description tables, the idle speed should be considered a normal characteristic of current vehicle design.
39 Affected Products
Vehicles
CHEVROLET | EXPRESS | 2010-2017 |
| CHEVROLET | SILVERADO | 2017 |
| CHEVROLET | SILVERADO 1500 | 2011, 2014 |
| CHEVROLET | SILVERADO 2500 | 2011-2016 |
| CHEVROLET | SILVERADO 3500 | 2013 |
| GMC | SAVANA | 2010-2017 |
| GMC | SIERRA | 2017 |
| GMC | SIERRA 1500 | 2014 |
| GMC | SIERRA 2500 | 2011-2016 |
| GMC | SIERRA DENALI | 2011-2013, 2015-2016 |
SEOCONTENT-START
Bulletin No.: PIP4912D
Date: Feb-2016
| Subject: | Duramax Intermittent High Idle Or Elevated Idle Descriptions |
| Models: | 2010 – 2016 Chevrolet Express, Silverado |
| 2010 – 2016 GMC Savana, Sierra | |
| Equipped with the 6.6 Duramax Diesel Engine RPO codes L5P, LGH and LML |
This PI was superseded to update Model Years. Please discard PIP4912C.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
A dealer may encounter a customer concern of an intermittent high idle. High idles may be commanded by the ECM for certain battery charging electrical loads or diesel particulate filter (DPF) cleaning processes.
These idle up speeds may occur with no input from the customer. Idle speed descriptions are included below.
G-VAN / GMT610 LGH IDLE SPEEDS
| REASON | RPM | Conditions/Constraints | Enablement | Trans Gear |
| BASE IDLE | 680 | Warm engine | P,N,D | |
| 680-850 | Base engine curve -Varies with coolant 680-850 temps from -40C to 150C | P,N,D | ||
| Manual elevated idle (UF3) | 1200 (default) | 680 -1300 RPM selectable via Tech2 | Set parking brake, cruise ON. cruise SET | P,N |
| Cold temp warm-up (EPR) | 680-1200 | RPM level varies with coolant temp disabled once coolant temp reaches 68C delayed for extremely low coolant temps | Enabled by selection through DIC | P, N |
| DPF Regen | 800 | During Regen and post-regen cooldown, & HC clean-out | ||
| AIC | N/A | AlC idle speed request disabled by platform for 2011 | ||
| Low battery voltage | 725 | Assist battery charging | Level 1 Based on Platform BCM module request | P,N |
| 850 | Further assist battery charging | Level 2 Based on Platform BCM module request | P,N | |
| 850 | Further assist battery charging | Level 3 Based on platform BCM module request | P,N |
C/K Truck / GMT900 / K2XX L5P and LML IDLE SPEEDS
| REASON | RPM | Conditions/Constraints | Enablement | Trans Gear |
| BASE IDLE | 640 | Warm engine | P,N,D | |
| 640-850 | Base engine curve -Varies with coolant temps from -40C to 150C | P,N,D | ||
| Manual elevated idle (UF3) | 1200 (default) | 680 -1300 RPM selectable via Tech2 | Set parking brake, cruise ON, cruise SET | P,N |
| Cold temp warm-up (EPR) | 640-1050 | RPM level varies with coolant temp disabled once coolant temp reaches 68C delayed for extremely low coolant temps | Enabled by selection through DIC | P,N |
| DPF Regen | 800 | During Regen and post-regen cooldown, & HC clean-out | Auto | P,N,D |
| AIC | N/A | AlC idle speed request disabled by platform for 2011 | None | P,N |
| Low battery voltage | 750 | Assist battery charging | Level 1 Based on Platform BCM module request | P,N |
| 900 | Further assist battery charging | Level 2 Based on Platform BCM module request | P,N | |
| 1050 | Further assist battery charging | Level 3 Based on Platform BCM module request | P,N |
C/K Truck / GMT900 / K2XX LGH IDLE SPEEDS
| REASON | RPM | Conditions/Constraints | Enablement | Trans Gear |
| BASE IDLE | 600 | Warm engine | P,N,D | |
| 600-850 | Base engine curve -Varies with coolant temps from -40C to 150C | P,N,D | ||
| Manual elevated idle (UF3) | 1200 (default) | 680 -1300 RPM selectable via Tech2 | Set parking brake, cruise ON, cruise SET | P,N |
| Cold temp warm-up (EPR) | 600-1050 | RPM level varies with coolant temp disabled once coolant temp reaches 68C delayed for extremely low coolant temps | Enabled by selection through DIC | P,N |
| DPF Regen | 800 | During Regen and post-regen cool-down, & HC clean-out | Auto | P,N,D |
| AlC | NlA | AlC idle speed request disabled by platform for 2011 | None | P,N |
| Low battery voltage | 750 | Assist battery charging | P,N | |
| 900 | Further assist battery charging | P,N | ||
| 1050 | Further assist battery charging | P,N |
Recommendation/Instructions
If a dealer has duplicated, or the customer description aligns with the speeds mentioned in the idle speed description tables, the idle speed should be considered a normal characteristic of current vehicle design.
Do not attempt repairs for intermittent high idle as described in this PI.
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.
SEOCONTENT-END
Bulletin No.: PIP4912E
Date: Dec-2016
To View or Download this Document Click Here
Bulletin No.: PIP4912D
Date: Feb-2016
To View or Download this Document Click Here
Bulletin No.: PIP4912C
Date: Aug-2014
To View or Download this Document Click Here
Bulletin No.: PIP4912B
Date: Nov-2013
To View or Download this Document Click Here
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