No Speedo and throwing codes
Thread Starter
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Champion
Joined: Jul 2005
Posts: 2,966
Likes: 3
From: Greeneville, TN
No Speedo and throwing codes
Hey all today i pulled out of the driveway slowly and truck seemed like it didn't wanna shift. I noticed my CEL was on not uncommon with my truck... I also took notice that my Speedo wasn't working. I checked the codes when I got home and had
P0500 Vehicle speed sensor "A"
P0442 EVAP system leak detected (small leak)
P1740 TCC or O/D solenoid performance
The P1740 is a common code even after getting the new trans put it. The trans shop said that he thinks my PCM has a short or something causing it to throw that code. The other two are new. My scanner has "fix assist" and when I clicked on that every code said "vss or oss signal circuit to pcm is open or shorted to ground vss or oss power circuit (8v) is open or shorted to ground". Could the short my trans guy believes is in my PCM finally causing more issues? Is there a way to check this issue before replacing the PCM?
Thanks for the help!
P0500 Vehicle speed sensor "A"
P0442 EVAP system leak detected (small leak)
P1740 TCC or O/D solenoid performance
The P1740 is a common code even after getting the new trans put it. The trans shop said that he thinks my PCM has a short or something causing it to throw that code. The other two are new. My scanner has "fix assist" and when I clicked on that every code said "vss or oss signal circuit to pcm is open or shorted to ground vss or oss power circuit (8v) is open or shorted to ground". Could the short my trans guy believes is in my PCM finally causing more issues? Is there a way to check this issue before replacing the PCM?
Thanks for the help!
Administrator
Joined: Apr 2010
Posts: 87,483
Likes: 4,223
From: Clayton MI
Your truck gets its cue for the speedo from sensor on top of the rear axle. They are fairly common failures..... Verify you are getting the 8 volts back to the sensor. (is your scanner getting anything for vehicle speed?) Output speed sensor is on the drivers side of the trans, before the O/D unit. I thought they had a separate code for those... but, if the PCM is getting signal from the rear wheel speed sensor, that would be my next sensor to have a close look at.
Thread Starter
|
Champion
Joined: Jul 2005
Posts: 2,966
Likes: 3
From: Greeneville, TN
Your truck gets its cue for the speedo from sensor on top of the rear axle. They are fairly common failures..... Verify you are getting the 8 volts back to the sensor. (is your scanner getting anything for vehicle speed?) Output speed sensor is on the drivers side of the trans, before the O/D unit. I thought they had a separate code for those... but, if the PCM is getting signal from the rear wheel speed sensor, that would be my next sensor to have a close look at.
Record Breaker
Joined: Dec 2018
Posts: 1,082
Likes: 170
If you're talking about the 2001 truck it doesn't have any 8 V sensors anymore, at least AFAIK. The *RE transmission has more wiring inside the transmission than the pre 96 trucks and it's not unheard of that this causes issues. Even more so as you have transmission codes. You could disconnect the connector at the transmission, the trans won't shift automatically anymore but you can manually shift 1,2,3 and R. If the Speedo comes back the problem is inside the transmission.
You can try to remove the output sensor at the transmission. Use a 1 inch wrench or socket. And put a dip pan under the transmission because it will leak. Check the sensor for debris. if none. Check the two wires at the connector. You could have broken wire. Your evap leak maybe a crack hose. Or a LDP pump. If you have 4 wheel ABS remove the rear differential sensor and check to see if there is a tone wheel on the differential carrier.
