CKP signal fault ….. advice needed
09-07-2023, 12:20 AM
#1
CKP signal fault ….. advice needed Getting CKP fault code and normal troubleshooting procedures not finding issue and seeking advice. GM LS3 swap using GM E67 ECM.
constantly get a CKP fault code for erratic signal on key up (ignition). Exhausted all GM and tropical troubleshooting procedures.
My last technique was to remove all wire terminals to ECM except 12v power, both grounds, CAN bus, CKP and coolant temp sensor. My objective was to eliminate all inputs except minimum required to read faults and not have the CKP fault then start plugging in wires until getting the CKP fault.
But even with all wires removed, still had CKP fault with key on/ignition (engine off). I then jumped a new CKP on a separate set of wires to bypass harness and connected to directly to ECM (all 3 CKP wires) … holding the CKP in hand allowing me to induce a trigger event by passing a wrench across the CKP. I should see 0 volts at signal wire (back probed at ECM) with wrench near CKP and 5v with wrench moved away from CKP as well as RPM indication on tach… , but often saw signal voltage remain at 0 volts while moving wrench back and forth….. indicating ecm is getting bad signal…..thus the erratic fault.
both CKP ground and 5v ref wires at connector load tested good and normal, and CKP producing strong magnetic field. I have 3 ECMs and all have same CKP fault.
I cannot figure out why the signal is not changing between 0 and 5v, but expect there’s an intermittent ground issue. This would normally point to a bad CKP but it functioned normal on other engine and occasionally I get faults for ECT and CMS (wires also tested normal).
any suggestions welcomed.
constantly get a CKP fault code for erratic signal on key up (ignition). Exhausted all GM and tropical troubleshooting procedures.
My last technique was to remove all wire terminals to ECM except 12v power, both grounds, CAN bus, CKP and coolant temp sensor. My objective was to eliminate all inputs except minimum required to read faults and not have the CKP fault then start plugging in wires until getting the CKP fault.
But even with all wires removed, still had CKP fault with key on/ignition (engine off). I then jumped a new CKP on a separate set of wires to bypass harness and connected to directly to ECM (all 3 CKP wires) … holding the CKP in hand allowing me to induce a trigger event by passing a wrench across the CKP. I should see 0 volts at signal wire (back probed at ECM) with wrench near CKP and 5v with wrench moved away from CKP as well as RPM indication on tach… , but often saw signal voltage remain at 0 volts while moving wrench back and forth….. indicating ecm is getting bad signal…..thus the erratic fault.
both CKP ground and 5v ref wires at connector load tested good and normal, and CKP producing strong magnetic field. I have 3 ECMs and all have same CKP fault.
I cannot figure out why the signal is not changing between 0 and 5v, but expect there’s an intermittent ground issue. This would normally point to a bad CKP but it functioned normal on other engine and occasionally I get faults for ECT and CMS (wires also tested normal).
any suggestions welcomed.
