Recieved codes P1293-P1294.Checked voltage on#878&#1087 wires,at VC ,only 2 volts.Unhooked harness at IDM,no opens or shorts.12v plus on green wire going to IDM. Do I need a new IDM or did I miss something?

 

From the manual :


Part 1...
NA20 DIAGNOSTIC TROUBLE CODES (DTCs) P1294 AND P1293: CHECK FOR VOLTAGE ON HIGH SIDE CIRCUIT

• DTCs P1294 and P1293 indicate an open circuit exists on the high side circuit between the IDM and the injectors. The following table lists the circuits to inspect while performing these pinpoint tests, based on the DTC retrieved during the KOEO On-Demand and Injector Electrical Self Tests.
  
  <TABLE cellSpacing=0 cellPadding=3 border=1><TBODY><TR><TH vAlign=bottom align=middle>DTC </TH><TH vAlign=bottom align=middle>High Side </TH><TH vAlign=bottom align=middle>Injector Bank </TH></TR><TR><TD vAlign=top align=middle>P1294 </TD><TD vAlign=top align=middle>878 (PK/YE) </TD><TD vAlign=top align=middle>Left </TD></TR><TR><TD vAlign=top align=middle>P1293 </TD><TD vAlign=top align=middle>1087 (OG) </TD><TD vAlign=top align=middle>Right </TD></TR></TBODY></TABLE>
• Key off.
• Disconnect connector on the bank with the code.
• Key on, engine off.
• Measure voltage on the suspect high side circuit Pin E on the injector vehicle harness connectors and battery ground.

Is voltage greater than one volt?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">GO to NA21 . </TD><TD width="50%">GO to NA24 . </TD></TR></TBODY></TABLE>
NA21 CHECK INJECTOR RESISTANCE

• Key off.
• Suspect injector valve cover connectors disconnected.
• Install Glow Plug Injector Adapter 014-00935 or equivalent.
• Measure resistance between high side and low side injector terminals on the adapter tool.

Is resistance less than 5 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">Fault may be intermittent. GO to NA15 . </TD><TD width="50%">GO to NA22 . </TD></TR></TBODY></TABLE>
NA22 CHECK HARNESS FOR OPEN

• Remove valve cover.
• Disconnect injector harness connector.
• Measure resistance between injector connector and exterior gasket connector.

Is resistance less than 5 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">REPLACE injector. RESTORE system. CLEAR DTCs and RETEST. </TD><TD width="50%">GO to NA23 . </TD></TR></TBODY></TABLE>
NA23 DETERMINE WHETHER GASKET OR UVC HARNESS HAS FAILED

• Disconnect UVC harness from gasket.
• Measure resistance across each contact in the gasket.

Is each resistance reading less than 5 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">REPLACE UVC harness. RESTORE system. CLEAR DTCs and RETEST. </TD><TD width="50%">REPLACE valve cover gasket. RESTORE system. CLEAR DTCs and RETEST. </TD></TR></TBODY></TABLE>
NA24 CHECK FOR OPEN IN HIGH SIDE CIRCUIT

• Key off.
• Disconnect IDM harness connector.
• Both connectors on the bank with the code disconnected.
• Measure resistance between suspect high side circuit at the IDM connector and Pin C and both suspect injector connectors.

Are both resistance readings less than 5 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">Fault may be intermittent. GO to NA15 . </TD><TD width="50%">REPAIR open in high side circuit. RESTORE system. CLEAR DTCs and RETEST. </TD></TR></TBODY></TABLE>
NA25 DIAGNOSTIC TROUBLE CODES (DTCs) P0263, P0266, P0269, P0272, P0275, P0278, P0281, P0284, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308

• Note: Only a California calibration will set a Continuous Misfire DTC. Both 49 state and California will set a KOER CCT DTC for a low or non-contributing cylinder. To run KOER Cylinder Contribution Test, refer to Quick Test description in Section 2 , Diagnostic Routines.
• If any of the following DTCs set in either Continuous or KOER Cylinder Contribution Test, this pinpoint test must be used to diagnose the fault.
  
  <TABLE cellSpacing=0 cellPadding=3 border=1><TBODY><TR><TH vAlign=bottom align=middle>CCT DTCs </TH><TH vAlign=bottom align=middle>California Continuous DTCs </TH><TH vAlign=bottom align=middle>Cylinder </TH></TR><TR><TD vAlign=top align=middle>P0263 </TD><TD vAlign=top align=middle>P0301 </TD><TD vAlign=top align=middle>1 </TD></TR><TR><TD vAlign=top align=middle>P0266 </TD><TD vAlign=top align=middle>P0302 </TD><TD vAlign=top align=middle>2 </TD></TR><TR><TD vAlign=top align=middle>P0269 </TD><TD vAlign=top align=middle>P0303 </TD><TD vAlign=top align=middle>3 </TD></TR><TR><TD vAlign=top align=middle>P0272 </TD><TD vAlign=top align=middle>P0304 </TD><TD vAlign=top align=middle>4 </TD></TR><TR><TD vAlign=top align=middle>P0275 </TD><TD vAlign=top align=middle>P0305 </TD><TD vAlign=top align=middle>5 </TD></TR><TR><TD vAlign=top align=middle>P0278 </TD><TD vAlign=top align=middle>P0306 </TD><TD vAlign=top align=middle>6 </TD></TR><TR><TD vAlign=top align=middle>P0281 </TD><TD vAlign=top align=middle>P0307 </TD><TD vAlign=top align=middle>7 </TD></TR><TR><TD vAlign=top align=middle>P0284 </TD><TD vAlign=top align=middle>P0308 </TD><TD vAlign=top align=middle>8 </TD></TR></TBODY></TABLE>
• Possible causes:
  • broken compression rings
  • inoperative injector assembly
  • leaking or bent valves
  • bent push rod
  • broken rocker arm bolts
  • bent connecting rod
• Perform KOEO On-Demand Self Test, KOER Cylinder Contribution Self Test, Retrieve/Clear Continuous DTCs.

Were any DTCs retrieved?

<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">REPAIR any concerns found. RESTORE system. CLEAR DTCs and RETEST. </TD><TD width="50%">GO to NA26 . </TD></TR></TBODY></TABLE>
NA26 CYLINDER NON-CONTRIBUTING

 

Part 2:....



NA26 CYLINDER NON-CONTRIBUTING

• Note: A/C must be off when running KOER Cylinder Contribution Self Test.
• Go to Section 4 , Diagnostic Subroutines, and perform Steps 8a, 8b, 8c, 8d, 9, 10a, 10b, 11, 11a, 11b, and 12.

Were any problems found after running all of the above steps?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">REPAIR any concerns found. RESTORE system. CLEAR DTCs and RETEST. </TD><TD width="50%">If base engine diagnostic checks pass, REPLACE injector assembly. If base engine does not pass, REPAIR concern. RESTORE system. CLEAR DTCs and RETEST. </TD></TR></TBODY></TABLE>
NA27 DIAGNOSTIC TROUBLE CODE (DTC) P1297

• Disconnect IDM harness connector.
• Measure resistance between both high side circuits at the IDM connector.

Is resistance greater than 10,000 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">GO to NA28 . </TD><TD width="50%">REPAIR short between both high side circuits. RESTORE system. CLEAR DTCs and RETEST. </TD></TR></TBODY></TABLE>
NA28 CHECK FOR INTERMITTENT SHORT BETWEEN BOTH HIGH SIDE CIRCUITS

• Measure resistance between both high side circuits at the IDM connector, Pins 22 and 23.
• Grasp the harness close to the IDM connector. Wiggle, shake harness while working towards the injectors.

Does resistance ever drop below 10,000 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">ISOLATE short circuit and REPAIR. RESTORE system. CLEAR DTCs and RETEST. </TD><TD width="50%">REPLACE IDM. RESTORE system. CLEAR DTCs and RETEST. </TD></TR></TBODY></TABLE>
NA29 DIAGNOSTIC TROUBLE CODES (DTCs) P1295 AND P1296

• DTCs P1295 and P1296 indicate that more than one fault exists on the right or left bank. A short and open on both the low side and high side can exist on the bank with the DTC.
  
  <TABLE cellSpacing=0 cellPadding=3 border=1><TBODY><TR><TH vAlign=bottom align=middle>DTC </TH><TH vAlign=bottom align=middle>BANK </TH></TR><TR><TD vAlign=top align=middle>P1295 </TD><TD vAlign=top align=middle>Right Bank </TD></TR><TR><TD vAlign=top align=middle>P1296 </TD><TD vAlign=top align=middle>Left Bank </TD></TR></TBODY></TABLE>
• Disconnect IDM harness connector.
• Measure resistance between each injector circuit one by one and battery ground from the IDM harness connector.

Are all circuits greater than 10,000 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">GO to NA30 . </TD><TD width="50%">If low side short was found, GO to NA1 to find short, then RETURN to this step. If high side short was found, GO to NA16 , then RETURN to this step. </TD></TR></TBODY></TABLE>
NA30 CHECK FOR SHORT TO B+

• Key on, engine off.
• Measure voltage of each injector circuit one by one between IDM harness connector and battery ground.
• Key off.

Was voltage present on any circuit?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">If low side short was found, GO to NA6 , then RETURN to this step. If high side short was found, GO to NA16 , then RETURN to this step. </TD><TD width="50%">GO to NA31 . </TD></TR></TBODY></TABLE>
NA31 CHECK FOR HIGH SIDE CIRCUIT SHORTED TOGETHER

• Measure resistance between high side circuits from the IDM harness connector Pins 23 and 24.

Is resistance greater than 10,000 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">GO to NA32 . </TD><TD width="50%">REPAIR short between both high side circuits. RESTORE system. CLEAR DTCs and RETEST. </TD></TR></TBODY></TABLE>
NA32 CHECK FOR OPEN CIRCUIT

• Disconnect all four valve cover connectors on both banks.
• Measure resistance between valve cover connector and IDM connector on all injector high side and low side circuits.

Are any circuits greater than 10,000 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">REPAIR open in suspect circuit. RESTORE system. CLEAR DTCs and RETEST. </TD><TD width="50%">GO to NA33 . </TD></TR></TBODY></TABLE>
NA33 CHECK FOR OPEN UNDER VALVE COVER

• Using Glow Plug Injector Adapter 418-F221 or equivalent, measure resistance between high side and low side of every injector circuit through the valve cover.

Are any injector circuits greater than 5 ohms?
<TABLE cellSpacing=0 cellPadding=3 width="92%" border=1><TBODY><TR><TH width="50%">Yes </TH><TH width="50%">No </TH></TR><TR><TD width="50%">GO to NA12 . </TD><TD width="50%">RECONNECT everything, CLEAR continuous DTCs and RERUN KOEO Injector Electrical Self Test and KOEO On-Demand Self Test. If DTC P1295 or P1296 reappears, REPLACE IDM. </TD></TR></TBODY></TABLE>


I'd be looking at the wiring as it crosses the head on the left side of the motor



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Thanks for all the info,I will double check all.My manual states ,test NA20,should read 10v at C term-s,KOEO.I am reading 2v.Just so you know,truck was running,with miss,#3 injector bad,double checking before tear down.Pulled connector on right valve cover to verify fuel knock would leave.Shut down,plugged connector in,would not re-start.

 

Finally got to look at my truck again.Still getting codes P1293-P1294.Unplugged connector at IDM read between high and low sides on all injectors,all avg. 2.8 ohms.Once again,with connector at vc unplugged-IDMconnected,reading 2.1v w/koeo.Checked wiring found nothing.Any ideas would be welcomed.Thanks Alan

 

UPDATE!!!!!!!!!!!!Just for the record.it was a BAD IDM.Guess they do go bad every now and then.