Author Topic: Cannot Connect  (Read 1324 times)

Rhapsody5

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Cannot Connect
« on: December 14, 2011, 05:02:51 PM »
Scan Tool:   OBDLink SX Scan Tool
Connection:   USB
Operating System:   Microsoft Windows XP Professional 32 Bit
      Version: 5.1.2600 Service Pack 3 Build 2600
Vehicle:      1999 Jeep Grand Cherokee (6 cylinder) USA
Engine:      6 cylinder gas, 242 cu. in. (4.0 liters)
Software:   OBDwiz  Version:  2.12.1.292
ScanTool Fault:   Connection of scan tool to vehicle PCM was not successful.  Message says only that there was an error experienced in the attempt to connect.  In response to error correction prompts, we can confirm that:
1.       The scan tool was connected properly.
2.       The vehicle ignition was set to ON.  (The engine will not run.  The starter engages and turns the engine over but there appears to be no fuel and we assume no ignition?)
3.       Connection Settings are correct between tool and laptop and we have successfully connected with a 2004 Chrysler Pacifica previously.

Vehicle Problem:   1999 Jeep Grand Cherokee will not start after normal shutdown.  The instrument cluster is not responsive (i.e.: when in run position the fuel gauge registers nothing - fuel warning light is on [there is gas in tank].   Check instruments light is on.   After the attempt at connecting the scan tool, the check engine light comes on).  Suspect that the PCM has crashed since it will not connect with the scan tool?   

Any suggestions as to how to affect connection with the PCM?  Will direct short in Crank Position Sensor or other input cause complete shutdown of PCM? 

Thanks, Rhapsody5

Vitaliy

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Re: Cannot Connect
« Reply #1 on: December 15, 2011, 02:09:30 AM »
Please post your Raw Data log (Diagnostics->Raw Data).

From your description, it does sound like the ECU may be damaged.
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Rhapsody5

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Re: Cannot Connect
« Reply #2 on: December 15, 2011, 01:27:49 PM »
Sorry, can not post "The communication logs (Raw Data tab of the Diag page);
nothing saved.  I was unaware that anything at all was being produced that could be recorded if there was no connection whatsoever.  Please advise what, if any, "raw data" will be generated during the CONNECTION process that would be helpful in diagnosing the connection problem. 

Rhap5

Vitaliy

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Re: Cannot Connect
« Reply #3 on: December 15, 2011, 07:27:23 PM »
Sorry, can not post "The communication logs (Raw Data tab of the Diag page);
nothing saved.  I was unaware that anything at all was being produced that could be recorded if there was no connection whatsoever.  Please advise what, if any, "raw data" will be generated during the CONNECTION process that would be helpful in diagnosing the connection problem. 

Rhap5

It would show commands that the computer sends to OBDLink, even if OBDLink is unable to communicate with the ECU.

Vitaliy
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Rhapsody5

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Re: Cannot Connect
« Reply #4 on: December 19, 2011, 12:43:09 PM »
Attached is the "Raw Data" log. 

Curious to know if anything revealed by the failure indications. 

Thanks, Rap5

Vitaliy

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Re: Cannot Connect
« Reply #5 on: December 19, 2011, 09:18:23 PM »
The voltage reading is 13.4V, which usually indicates that the engine is running. Do you have the battery hooked up to an external charger?

Before replacing the PCM, I would check the connectors & wiring.

Vitaliy
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Rhapsody5

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Re: Cannot Connect
« Reply #6 on: December 20, 2011, 11:49:17 AM »
Yes, the 13.4 volts was due to jumping the Jeep's battery with another vehicle. 

We will follow up on re-checking all connections and wiring.  We have inspected all relays, fuses and re-seated various grounding wires (to assure good contact) but we have not disconnected and re-installed the connectors between the OBD port and the PCM.  I suspect that some connector has oxidized and is no longer conducting (?). 

Thanks for your comments; we will advise the outcome. 

Rap5