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Has anyone seen factory engine harness of 2003 Acura CL Type S 6 Speed M/T that swaps CKP1 and CKP2 signal inputs to the ECU?
I recently purchased a 2003 Acura CL Type S 6 Speed M/T. It's throwing P0336 code. In trying to isolate the problem, I found this post/thread: https://acurazine.com/forums/2g-cl-p...-p0336-957910/, which noted at least two found replacing CKP2 solved the problem despite 336 being a code for CKP1. So I did a circuit test and found:
CKP1 signal is wired to ECU pin A08
CKP2 signal is wired to ECU pin A12
Furthermore I found CKP1 signal was in pin 2 of CKP1's connector; rather than pin 1 as shown in service manual. (The orange and green wires in the attached pictures are inserted into the pins that have continuity to the ECU).
I've ordered both CKP sensors and plan to change wiring to match service manual. However given my car was an early instance of the M/T (it was manufactured 5/02), I was curious if there was potentially different factory wiring/pinouts in the early builds (as the engine wiring harness doesn't appear it has been opened or altered).
Update: Front CKP1 sensor (37500-PGE-A11) hasn't shipped/arrived yet, but rear CKP2 sensor (37506-PGE-A12), which installs on the Transmission Bell Housing on the 6-speed, arrived.
I installed it and it resolved the P0336 code. So like 619cr suggested, no rewiring needed.
This makes a little more sense knowing that CKP2 output signal is wired to CKP1 input of the ECU. Thus ECU reports "P0336 Crankshaft Position Sensor A circuit Range/Performance", a CKP1 DTC.
While I'd like to know more conclusively how the ECU is programmed for CKP1 and CKP2 inputs, empirical evidence indicates ECU operates correctly with CKP1 output signal going to CKP2 ECU input.
However if I ever need to install the new CKP1 sensor, I'll be reluctant to think the new CKP1 sensor has its ouput signal on pin 2 rather than pin 1 (as specified in the service manual).
Yes I used an RSX CKP, just guessing it was the same as 37506-PGE-A12 (which is difficult or impossible to source). Surprised you asked; and I found #100 of referenced thread of interest. Did you find long-term, the RSX CKP you used continued to operate correct, keeping the CL6 ECU (37820-PGE-A11) happy?
Yes I used an RSX CKP, just guessing it was the same as 37506-PGE-A12 (which is difficult or impossible to source). Surprised you asked; and I found #100 of referenced thread of interest. Did you find long-term, the RSX CKP you used continued to operate correct, keeping the CL6 ECU (37820-PGE-A11) happy?
Yes, over a year with rsx sensor and stock 6spd ecu.
After getting derailed from this project for quite some time, I recently reattacked it.
The problem: A camshaft position sensor (CMP) was the culprit.
As noted earlier in this thread, found that P0336 which is a CKP sensor A code was resolved by replacing CKP2 sensor. The documentation for this car that I have (shown earlier in this thread) does not match the way the car is built:
Engine wiring harness connects CKP1 sensor to CKP2 input to the ECU
Engine wiring harness connects CKP2 sensor to CKP1 input to the ECU
The two (2) wires that send the CKP1 signal are reverse of what is documented (but that doesn't really matter as these 2 wires form a circuit that is closed when a trigger point on the camshaft pulley passes over a camshaft sensor).
So after resolving the P0336 code, then starting getting P0385 (Crankshaft Position Sensor B Circuit Malfunction) and the engine wouldn't rev past 3 or 4K.
This combined with documentation mismatch and sound advice from @619rcr, I decided to look at the camshaft sensors. This led to resolving the problem.
The previous owner blew the original engine with timing belt break; and had a JDM replacement engine installed from an automatic transmission vehicle. Thus the cramshaft pulley and sensors were swapped as well as the crankshaft sensor and pulley gear with proper reluctor teeth. The problem was that the camshaft pulley cover (pointed to with blue arrow in image below) which houses the CMPs wasn't installed correctly. The CMPs' wiring harness was crimped between the pulley cover and the head (in the area pointed to with green arrow in image below) just enough to cause slight collision with cam pulley trigger points (one is circled w/ yellow oval in image below) and one of the CMPs (pointed to with red arrow). You can see the CMP sensor was actually being scrapped by the trigger points on the cam pulley. (The damaged CMP is shown in the upper right of the image below.)
After replacing the damaged CMP sensor (37840-PGE-A11) the engine then ran well and didn't complain about reving past 4K rpm, but was still getting the P0385.
To be fully convinced that the ECU reports CKP Sensor A DTCs for CKP B issues and vice versa, I disconnect CKP B. The engine ran pretty much the same but then also threw DTC P0336 in addition to P0385.
After reconnecting CKP2 sensor and replacing CKP1 sensor (37500-PGE-A11), DTC P0385 cleared and the engine runs A1.
Takeaways:
Both documentation and the ECU for the 2003 Acura CL M/T have CKP1 and CKP2 sensors reversed.
Wire on pin 2 of the wiring sub-harness for CKP1 sensor (circled with green oval in lower right of image) is used as the CKP signal. (This turns out to be no issue as noted above.)
When CMP signal isn't quite right ECU may not report any CMP related DTC
Use extra care when installing the camshaft pulley cover that houses the CMPs. It is very easy for its wiring harness to get lodged between the cover and the head.
Last edited by brianwillard.tn; 03-20-2024 at 08:11 AM.
The previous owner blew the original engine with timing belt break; and had a JDM replacement engine installed from an automatic transmission vehicle.
Use extra care when installing the camshaft pulley cover that houses the CMPs. It is very easy for its wiring harness to get lodged between the cover and the head.
It appears from your analysis the previous owner did not 'modify' the JDM front head in the areas (red arrows) below?
The JDM front head is from an automatic J32 Japanese model; therefore, one would think it has the same / similar casting as an USDM automatic J32A2.
The factory front head for the manual J32A2 has differences from the factory front head for the automatic that need to be accounted for when mounting the front cam sensor mounting plate as shown in the excellent video below.
Automatic USDM J32A2 front head modifications to make six speed compatible:
Interesting. I wish I had this info when I had the cam pulley plate off. I'm quite certain I got the plate installed correctly without any collision with the CMP sensors or the wiring harness. Either way, I don't plan to remove the cam pulley again anytime soon. But if the ECU starts throwing CKP or CMP DTCs or the engine refuses to rev past 4K, I won't hesitate to start there Thanks for sharing the info!
09-16-2022, 07:25 AM
Thanks for sharing the info!
