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Juan Crespo
Juan Crespo, Tech Trainer
Category: Car
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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ISUZU RODEO: why do I not have 5v on ckp and knock sensors

Customer Question

why do I not have 5v on ckp and knock sensors on this 01 rodeo 2.2 a/t fed???
Submitted: 1 year ago.
Category: Car
Expert:  Juan Crespo replied 1 year ago.
Hi there. Welcome to our site. Actually, the CKP is on a separate circuit and does not work with a 5V reference signal. With ignition on, the Green wire at the CKP should have ignition feed voltage (>10V). What is it you're trying to diagnose? A "CRANKS BUT WON'T START" condition?
Expert:  Juan Crespo replied 1 year ago.
It is possible that the engine could be starting so out of time because the timing belt is off or worn and stretched.
Here are the steps to test the CKP and its circuits:
28. Raise and support vehicle. Disconnect Crankshaft Position (CKP) sensor connector. Turn ignition on. Using a test light connected to ground, probe ignition feed circuit at CKP sensor harness terminal No. 2 (Green wire). If test light does not illuminate, repair open Green wire. Retest system. If test light illuminates, go to next step.
29. Connect test light between ignition feed circuit at CKP sensor harness terminal No. 2 (Green wire) and ground circuit terminal No. 3 (Black/Red wire). If test light illuminates, go to step 31 . If test light does not illuminate, go to step 32.
30. Check for open or short circuit in Green wire between CKP sensor and PCM. Repair as necessary. Retest system. If problem was not found, go to step 33 .
31. Replace CKP sensor. Retest system. If problem is still present, go to step 34 .
32. Check for open or short circuit in Yellow wire between CKP sensor terminal No. 1 and PCM. If problem was not found, go to next step. If problem was found, repair Yellow wire as necessary.
33. Replace and reprogram PCM.
34. Test for fuel contamination. If fuel is not contaminated, go to next step. If fuel is contaminated, clean fuel system as necessary. Replace fuel filter and verify all fuel injectors are delivering fuel. If problem was not found, go to next step.
35. Check for these possible conditions:
 Faulty camshaft timing belt.
 Leaking or sticking valves or rings.
 Excessive valve deposits.
 Loose or worn rocker arms.
 Weak valve springs.
 Leaking head gasket.
Best Regards.
Customer: replied 1 year ago.
ckp circuit is intact. cmp sensor circuit is intact. I have been through all 5v reference circuits and found no opens nor shorts. PCM has all powers ang grounds. Still, w ckp unplugged, I read 1.4v in and out of pcm to ckp.
Customer: replied 1 year ago.
fuel system is clean, new filter and fuel. plenty of pressure. no vacuum leaks. Can not figure out why pcm is not supplying 5v to ckps and have 3 that perform in the same manner
Expert:  Juan Crespo replied 1 year ago.
The fact that you say the engine starts with all three PCMs leads me to believe the problem might not be related to either CKP or PCM circuits and instead is due to engine timing being off. If I were you, I would definitely check the timing belt to make sure it's aligned right - I've attached a graphic for you to use as reference if you'd need to. Best Regards.
Customer: replied 1 year ago.
PID Values via Prodemand for this vehicle have C5, ckp sensor low at 4.98 v w ign. on, and C6,ckp sensor high at 0vw ign. on. I have to trust Prodemands PID values over the value you have stated, >10v on green wire. Values remain the same w or w/o sensor plugged in.
Customer: replied 1 year ago.
I have new timing belt and temsioner. timing is perfect according to manufacturer spec. and stays in range while idling.
Customer: replied 1 year ago.
Bill Fisk remanned this head. compression is better than good. ?????
Customer: replied 1 year ago.
I can select this phone option if ok with you.
Customer: replied 1 year ago.
Nevermind it has disappeared from my screen
Expert:  Juan Crespo replied 1 year ago.
I guess you mean PCM PIN voltages with the sensor connected. Did you do the test with the test light Isuzu recommends on step 29? - "29. Connect test light between ignition feed circuit at CKP sensor harness terminal No. 2 (Green wire) and ground circuit terminal No. 3 (Black/Red wire). If test light illuminates, go to step 31 . If test light does not illuminate, go to step 32"
Customer: replied 1 year ago.
I would like for you to tell Ask.com to refer me to someone else because I have not received a plausible answer to the question I have presented
Customer: replied 1 year ago.
Is Prodemand wrong about 5v reference out, term. C5 blue, to ckp sensor?
Customer: replied 1 year ago.
You are referring to Cam Pos. sensor which I have no qualms with.
Customer: replied 1 year ago.
Blk/Yel Cam term. 3 has ignition feed.
Customer: replied 1 year ago.
1.4v out and in to and from ckp sensor w no change if plugged in. Why?
Expert:  Juan Crespo replied 1 year ago.
I'll opt out and re-open the question so other experts can chime in. Please do not reply or the site will revert the question back to me. Best Regards.
Customer: replied 1 year ago.
Have you re-opened this question yet??? I have no further comm.s from anyone about this.

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