- Excavator
- 320 (S/N: BR61-UP; ZBN1-UP; YBP1-UP; YCP1-UP; HEX1-UP)
- 323 (S/N: BR91-UP; DWF1-UP; YBL1-UP; HDT1-UP; KTY1-UP; RAZ1-UP)
- 330 (S/N: WCH1-UP; KEL1-UP; PFN1-UP; LHW1-UP)
- 336 (S/N: SP91-UP; JHD1-UP; TPK1-UP; FEL1-UP; YBN1-UP; DKS1-UP; GDY1-UP)
- 336 GC (S/N: GSF1-UP; HFJ1-UP)
- 340 (S/N: TYH1-UP; GMJ1-UP; WDN1-UP)
- 349 (S/N: LKG1-UP; RYG1-UP; RBY1-UP)
- 352 (S/N: MGR1-UP; KZY1-UP; HSZ1-UP)
- 323 (S/N: BR91-UP; DWF1-UP; YBL1-UP; HDT1-UP; KTY1-UP; RAZ1-UP)
- Multi Terrain Loader
- 287D (S/N: STK1-UP)
- Track-Type Tractor
- D3K2 (S/N: KF21-UP; KL21-UP)
- D4K2 (S/N: KM21-UP; KR21-UP)
- D5K2 (S/N: KW21-UP; KY21-UP; RRE1-UP)
- D6K2 (S/N: EL71-UP; MGM1-UP; DFR1-UP; JTR1-UP)
- D6N (S/N: MG51-UP; GB61-UP; SGG1-UP)
- D6T (S/N: 2D21-UP; CR31-UP; 2B31-UP; MB51-UP; AK71-UP; MH71-UP; 7C91-UP; SGA1-UP; RAD1-UP; STE1-UP; JML1-UP; MEL1-UP; JNM1-UP; WRN1-UP; K1R1-UP; KMR1-UP; WES1-UP; HYT1-UP; SGT1-UP; NDY1-UP; TMY1-UP; HTZ1-UP; SGZ1-UP)
- D8T (S/N: FMC1-UP; MLN1-UP; FCT1-UP)
- D9T (S/N: TWG1-UP; REX1-UP)
- D4K2 (S/N: KM21-UP; KR21-UP)
Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.
Problem
Reports received regarding intermittent and startup satellite connection issues on MS952 and MS955 Global Navigational Satellite System (GNSS) receivers.
The part numbers of the GNSS receivers are listed in Table 1.
| Part Number | Part Name | Description |
|---|---|---|
| Satellite Receiver Gp | MS952 GNSS Receiver | |
| Satellite Receiver Gp | MS955 GNSS Receiver |
| |
| Illustration 1 | g06407160 |
|
Location of GNSS receiver | |
| |
| Illustration 2 | g06407185 |
|
GNSS receiver (A) Power LED (B) Datalink LED (C) Satellite LED | |
Intermittent satellite connection issues are often related to a poor connection between the GNSS receiver and the GNSS antenna, the cable connection between the GNSS antenna and the GNSS receiver if broken entirely will cause a consistent satellite connection problem.
There was a problem found with the GNSS antenna connection internal to the MS952 GNSS receiver on some of the units built early in 2016 and previous. An improvement was implemented during production on the MS952 GNSS receiver, but all MS955 GNSS receivers have the improvement.
However, there has been a problem found with the MS955 GNSS receiver that on some startup of the system, the GNSS receiver will fail to entirely power up and will stop in boot mode where all three status LEDs will be on solid and the GNSS receiver will fail to report satellite connections.
| LED | Off | Slow Flash | Flash | Fast Flash | On solid |
|---|---|---|---|---|---|
| Power | No power | - | - | Beta test period expired(1) | Power on |
| Datalink | No CMR data received or too few satellites | - | CMR data type 0 being processed | - | 10 Hz CMR data being processed |
| Satellite | No satellites being tracked | Tracking four satellites or more | - | Tracking three satellites or less | Monitor Mode(2) |
| (1) | In addition to the power LED, the data link and satellite LEDs will also flash, and at the same rate as the power LED. |
| (2) | In addition to the satellite LED, the power LED will also be on solid, and the data link LED will flash. |
This issue where all the LEDs are On Solid has not been seen on MS952 GNSS Receivers, so it is believed to be an MS955 GNSS receiver-specific issue. Refer to Table 2 for LED status.
Solution
Caterpillar is aware of this issue and working towards a permanent solution. As an interim action, follow the below recommended instructions.
MS952 GNSS Receivers
For MS952 GNSS receivers that experience intermittent or consistent satellite connection issue where all the cables and connectors between the GNSS receiver and the GNSS antenna have been verified, the issue could be related to the internal GNSS antenna connection improved in 2016.
Improvement has been made on all MS952 391-2010 Satellite Receiver Gp components with a component serial number (aaabJcccTJ), where aaa is greater than 67 when b is equal to 6 or aaa is any number when b is greater than 6. The process for soldering the central TNC connector pin internal to the unit was made more robust and additional unit testing is completed to verify a good connection on every unit.
MS955 GNSS Receivers
For MS955 GNSS receivers that experience startup failure where no connection to satellites is possible and all three status LEDs are On Solid, then the unit is experiencing the problem being investigated. Replace the failed part with the same part number.
In the event of failure, provide the pictures and additional information along with TIB Media Number, M0104762, CPI # 404666, Machine S/N, and part hours at failure to your Dealer Technical Communicator (TC). Request the Dealer TC to submit the information through CPI Feedback within the Service Information Management System (SIMSi) for further investigation.