2004 Cadillac DeVille Will Not Crank-Engine Has Been Replaced

Kevin C: Put a good used motor in car……now when I try to start the security lite blinks (like it is supposed to) until I put in the key when I turn key to on position the only thing that comes up is the trans selector p-r-n etc but no line under the gear you’re in, no other dash lights. The fuel pump continues to run it doesn’t cycle off if no start. Also no radio …climate control comes on until you turn key to start and then it goes out…when you turn key off 3 or 4 seconds the bottom half of the dash lights up before chime goes off and interior lights come on..help!

Sparky: The first things I would suspect would be a battery with a very low charge, dirty or corroded battery terminals (especially the positive cables that are double stacked), a bad engine ground or body  ground.

What was the reason for changing the engine?

Do you have a multimeter to test with?

Kevin C:  Battery good terminals clean…all grounds(g100,g101,g102,g103,g104,g105,g106,g110) check out. My original Northstar ate a head gasket when the bypass tube clogged and it overheated… replacement motor is a runner I was pretty sure it had to be a ground but I find nothing bad unless one is hiding. I took the fuse panel in the engine compartment apart again and checked the 3 plugs and re tightened the power cables and it worked one time…pump cycled on and off tranny selector line came on radio on fuel gauge on and cranked over   but I didn’t try to start it filled fluids and now ready to start and nothing.

Sparky: What do you have to test with: scan tool, multimeter or test light?

Kevin C: I have all 3 but just to let you know my scan tool keeps saying link up problem so I assume the pcm is not sending a signal.

Sparky: I recommend starting with getting the scan tool communicating. Check to make sure there is a good ground to terminals 4 (black) & 5 (black/white) of the DLC. Also check for battery power at terminal 16 (orange) of the DLC. Be sure to check these against a known good ground. Even if you have to connect an extra wire to the negative battery terminal.

Kevin C:  I found problem…middle connector to pcm was not fully snapped into place all good now and cranking away..just wont start. I give it a shot of starting fluid and it tries to but just cant get over the hump (makes you want to grab the distributor and crank up the timing.. if it was back in the day) any ideas to get me running? Thanks

Sparky: Back to checking codes and data in the PCM. See what is there now and then disconnect both battery cables at the battery. Hold the cable ends together for about one minute. This will clear any logic lock. Reconnect the cables to the battery and see if there are any codes before and after trying to start the engine.

Kevin C: Checked codes before battery disconnect P0118, P0122, P0300, P0335, P0340, P0352, P0355, P0357, P0385, P0405,P0410, P0442 & P0741 all were confirmed and then pending and after battery disconnect they all were still there.


The bulk of those codes have to do with several sensors and ignition coils. To have that many real codes I would suspect one of several things.

Mismatched harnesses; was the original engine harness from your vehicle installed on the replacement engine or was used engine with it’s harness installed in your car? What year make and model of car did the donor engine come from?

Poor connection at the PCM C2 connector. Check for bent pins.

Check for 5 volt power on the gray wire at the TPS and ground on the black wire at the TPS.

Kevin C: I used the harness that came with the motor and I was told that donor car was an 04 Deville just like mine which pcm connector is c2?? The middle connector was the one that was not completely on that got me to the point I am now.  I will check voltage to tps tomorrow and let you know but in the mean time if you could let me know the c2 location?

Sparky: The C2 connector will black in color and will have 73 cavities for terminals. Not all cavities will have wires installed though.

Kevin C: I checked tps gray wire and got 4.95 volts at black. I got 9 volts(not sure I got a good probe into the black wire) when I checked the voltage at the blue wire I got 4.8 volts there at closed throttle and as throttle opened the voltage jumped around but only by a couple 10ths.

Sparky: You are missing a good ground on the black wire at the TPS. As a quick test only, add an extra ground wire to the black wire at the TPS. See if the voltage on the blue wire now responds properly when the throttle is moved.

Kevin C: We are making progress…..the c2 connector was not fully engaged…I cleared the codes and got the car started…..has a pretty good miss and wont idle unless I feather throttle let it run 5 or 6 minutes. Pulled codes again P0201, P0201, P0335, P0352, P0354 & P0358. We are getting closer want to thank you for all your help…..now lets get this puppy running good.

Sparky: The P0201 code is for a problem with the #2 injector circuit so I would check to make sure that injector harness is properly connected. You listed that code twice so I am not sure if you may have another p020? code or not? If you do check that injector as well. The p0335 code references a fault with the Crank sensor “A” (top position). Check to insure it is securely connected. The codes P0352, P0356 & p0358 are all coil codes for cylinders 2,6 & 8. Check to make sure that the coil assemblies harness is properly installed. If it is, you may want to swap the coil assembly from the other engine. Codes P0335 versus P0352, P0356 & P0358. The first code could induce the rest and the last three could induce the first.

Kevin C: I have code P0201 and P0203, so your telling me that P0201 is for cylinder 2 and then P0203 is cylinder 4?? The other P0352 and P0354 and P0358 are all on the front bank also(at least they are easy to get to) I will clear all the codes in the morning and check the connections good and fire it up. I have another coil assembly if it throws those codes again…will let you know thanks again.

Kevin C: When you say #2 injector circuit do you mean cylinder 2?? Reader said injection circuit open cylinder 1??

Sparky: Sorry my fault.  P0201 would be for injector number 1 and p0203 would be for injector number 3.

Kevin C: I will check 1 and 3 with a noid light tomorrow (is there another way?) and maybe I will put the other coil harness on the front bank.

Good news car is running and running good…..c2 connector was not making good contact…cleared all the codes and drove car half an hour now I get po123 and po405 tps and egr….I cleared these and scan tool said 1 code remained rerun the codes and I cant get rid of the po123..why wont it erase??

Sparky: The code setting criteria for P0123 is that the PCM sees 4.7 volts from the TPS for more than 1 second. If you can see data stream in your scan tool monitor this voltage and compare it to actual measurement at the TPS. If you cannot see data you will need to check the signal wire at the PCM and compare it to the reading at the TPS. You can also disconnect the TPS connector and run the vehicle for a little while and see if the code shifts to a P0122, signal voltage less than .16 volts for more that 1 second.

Kevin C: Everything is working out pretty good on my 04 Deville, I was having po123 codes and po405. I replaced the tps plug and got rid of the po123. Now for the po405, I clear the codes and the mil light goes off but code reader says 1 code remaining… I can drive the car 30 miles and the mil light wont come on until I shut it off. When I restart…there it is again(mil) with po405 any advice???

Sparky: Can your scan tool read data and perform bidirectional controls?

Kevin C:  It reads data and has a freeze frame function but no bidirectional codes…..

Sparky: The P0405 code sets when the EGR valve position sensor is less than .11 volts for more than two seconds. Start by monitoring that data and see if the voltage is indeed low. Closely inspect the EGR valve terminals to see if any are damaged. If damage is found repair and re test. If no damage is found disconnect the EGR harness and check data. It should be near 0 volts. Using a 3 amp fused jumper wire connect the Brown wire at terminal C to the Gray wire at terminal D. Check the reading it should be near 5 volts. There are two gray wires at the EGR harness. Make sure it is terminal D. If your readings were good more than likely the EGR valve itself is faulty. Beyond this test you really do need bidirectional controls or at the very least a really good multimeter, backprobe connectors, time and patience.

Kevin C: OK… that code may have to wait. Thanks again…your help has been invaluable

Share Your Experience: