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Restoring a 2003. I have p0650 code on the pcm. Ive had the dash out working on the hud, but not related to this problem. Not thrilled to take the dash out again so I came up with this test myself. I wired a bulb at the points shown in the pictures. Still bulb doesn't light up during ignition and the code won't stay cleared. Please weigh in experts.
Where exactly is the ground side of your light connected to ??…I would take a 12 volt test light and connect it to battery positive and go to pin 46 (brown/white)of the C2 connector at the PCM and back probe it (with a T pin)...turn the key on and see if the test light illuminates…if it doesn’t the MIL Control PCM driver is not working !!…bad PCM ???…the driver will ground the circuit when the key is turned on for your bulb check. What is circled in red ???
I also find it odd that the live data from the pcm doesn't say anything about the MIL circuit. But the instrument panel live data does mention the MIL circuit. These wiring diagrams I found on here show the MIL control from the PCM. So what gives?
Where exactly is the ground side of your light connected to ??…I would take a 12 volt test light and connect it to battery positive and go to pin 46 (brown/white)of the C2 connector at the PCM and back probe it (with a T pin)...turn the key on and see if the test light illuminates…if it doesn’t the MIL Control PCM driver is not working !!…bad PCM ???…the driver will ground the circuit when the key is turned on for your bulb check. What is circled in red ???
connector #1 pin b4 underhood fuse box looks like the ground from the pcm driver. I have my little test bulb tied in there and connector #1 pin f11 underhood fuse box. With. 1 amp inline fuse. The red circle is my little test bulb sticking out the side of the underhood fuse box. From there I figure its just a short wire down to the PCM.
I have a high end scan tool and mine does not show it in live data in my IP or Engine…if you can look at IP live data I’m assuming you have a decent scan tool…it’s not really a data PID per se…if I go to output controls I can bi directionally command the MIL control driver on and off while the engine is running…power for the bulb comes from Ignition 1 voltage and when the PCM grounds it the light comes on !!…you have a pic of that MIL data PID ??
connector #1 pin b4 underhood fuse box looks like the ground from the pcm driver. I have my little test bulb tied in there and connector #1 pin f11 underhood fuse box. With. 1 amp inline fuse. The red circle is my little test bulb sticking out the side of the underhood fuse box. From there I figure its just a short wire down to the PCM.
Oh, OK !!…it is probably best to back probe right at the PCM (right at the horses mouth) to remove any doubt of a wiring issue…wouldn’t be a bad idea to remove that PCM connector and do a quick visual inspection of the pins.
I have a high end scan tool and mine does not show it in live data in my IP or Engine…if you can look at IP live data I’m assuming you have a decent scan tool…it’s not really a data PID per se…if I go to output controls I can bi directionally command the MIL control driver on and off while the engine is running…power for the bulb comes from Ignition 1 voltage and when the PCM grounds it the light comes on !!…you have a pic of that MIL data PID ??
this picture is from the instrument panel inputs. My scanner can't do bidirectional and I don't see an output for the MIL in the PCM. this is the only thing i see referencing that circuit at all.
this picture is from the instrument panel inputs. My scanner can't do bidirectional and I don't see an output for the MIL in the PCM. this is the only thing i see referencing that circuit at all.
You will need a bidirectional scan tool to see the output controls…this is the screen shot from my Autel with key on engine off…MIL is lit but my MIL input PID shows off…not sure when you should see it on.
Oh, OK !!…it is probably best to back probe right at the PCM (right at the horses mouth) to remove any doubt of a wiring issue…wouldn’t be a bad idea to remove that PCM connector and do a quick visual inspection of the pins.
you're a trooper, thanks for the dialog about my issue. I'm starting to think its either at the pcm connector or God forbid its in the driver. Because my test bulb should have worked. Never changed a PCM before. Guessing the only hard thing about it is the $$$$
To surmise; I was looking for confirmation from an expert for the following.
My test bulb accurately isolated the circuit to rule out the instrument panel connectors and bulb. I effectively ruled out all wiring past the underhood fuse box?
didn't want to turn the wrong direction and start looking at the PCM if I could have missed it in the dash.
OK, so what if you had a open circuit one inch from the PCM connector...your test is invalid...like I said disconnect the PCM C2 harness and work up toward the MIL lamp !!
OK, so what if you had a open circuit one inch from the PCM connector...your test is invalid...like I said disconnect the PCM C2 harness and work up toward the MIL lamp !!
10-4. Thanks for your help. I'll start at the PCM. Wish me luck.
Ok, let us know what you find !!…don’t know if you’ve ever taken one of the PCM connectors off but you squeeze the ends of the gray cover to remove it…it’s easy to break the 2 little clips on each end !!
Got the car in the air and accessed the PCM. Connections look good. Disconnected and cleaned connections. Can't find a store that sells back probes. Might try a sewing needle for testing.
Got the car in the air and accessed the PCM. Connections look good. Disconnected and cleaned connections. Can't find a store that sells back probes. Might try a sewing needle for testing.
You can find T pins at craft stores or Amazon and back probes on Amazon !!
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Mil circuit help
and I don't see an output for the MIL in the PCM. this is the only thing i see referencing that circuit at all.
