code 46 help needed
Thread Starter
Advanced
Joined: Feb 2007
Posts: 54
Likes: 0
From: Woodville Alabama
code 46 help needed
This is on a 90 coupe, 92,000 miles.
Went for a short drive yesterday, was running well until engine just shut off and would not restart. Had it flatbedded home and started diagnosing today. Security light goes out as it should with switch on and I get no SYS light.Chck engine light not on.I have spark and fuel to rail (came out the schrader valve). Used a jumper to get the codes and it has code 46.I followed the troubleshooting in the FSM. I cant find a open or short in ckt 229, so went on to check the ccm. It has no codes,which I thought would have a code 54...fuel enable failure. At this point I am stuck. Is there any way to make sure of why this will not start, before I have to replace the ccm, which is what the FSM says is next? I'm assuming that if the engine will turn over then its not a bad key or ignition problem that I could bypass with the available bypass harnesses. I'm also assuming that if it is a vats problem, its at the fuel enable circuit. I know I'm doing a lot of assuming here and would not be hurt to be corrected. I have searched this forum for this but most posts deal with non cranking issues and the rest I find dont help to much. Thanks for any input and suggestions
Went for a short drive yesterday, was running well until engine just shut off and would not restart. Had it flatbedded home and started diagnosing today. Security light goes out as it should with switch on and I get no SYS light.Chck engine light not on.I have spark and fuel to rail (came out the schrader valve). Used a jumper to get the codes and it has code 46.I followed the troubleshooting in the FSM. I cant find a open or short in ckt 229, so went on to check the ccm. It has no codes,which I thought would have a code 54...fuel enable failure. At this point I am stuck. Is there any way to make sure of why this will not start, before I have to replace the ccm, which is what the FSM says is next? I'm assuming that if the engine will turn over then its not a bad key or ignition problem that I could bypass with the available bypass harnesses. I'm also assuming that if it is a vats problem, its at the fuel enable circuit. I know I'm doing a lot of assuming here and would not be hurt to be corrected. I have searched this forum for this but most posts deal with non cranking issues and the rest I find dont help to much. Thanks for any input and suggestions
Last edited by chck4342; Jul 6, 2008 at 09:16 PM.
Thread Starter
Advanced
Joined: Feb 2007
Posts: 54
Likes: 0
From: Woodville Alabama
A small update...I just pulled the connector to a injector and probed with a test light. I get power at both terminals with key on, but no change when I'm cranking. Shouldnt the light blink on and off when cranking?
Safety Car
Joined: Oct 2007
Posts: 3,816
Likes: 0
From: :45 minutes from everywhere / E-I-E-I-O
Saying you can't find a short is not the same as saying you know for sure there is NO short.
You have to test an entire length of wire at each link in the circuit - from PIN TO PIN. Not the easiest task, but it's pretty cheap to do electrical diagnostic, as opposed to buyin' parts blindly.
I have to do this wiring diagnostic stuff in the morning...
You have to test an entire length of wire at each link in the circuit - from PIN TO PIN. Not the easiest task, but it's pretty cheap to do electrical diagnostic, as opposed to buyin' parts blindly.
I have to do this wiring diagnostic stuff in the morning...
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
This is on a 90 coupe, 92,000 miles.
Went for a short drive yesterday, was running well until engine just shut off and would not restart. Had it flatbedded home and started diagnosing today. Security light goes out as it should with switch on and I get no SYS light.Chck engine light not on.I have spark and fuel to rail (came out the schrader valve). Used a jumper to get the codes and it has code 46.I followed the troubleshooting in the FSM. I cant find a open or short in ckt 229, so went on to check the ccm. It has no codes,which I thought would have a code 54...fuel enable failure. At this point I am stuck. Is there any way to make sure of why this will not start, before I have to replace the ccm, which is what the FSM says is next? I'm assuming that if the engine will turn over then its not a bad key or ignition problem that I could bypass with the available bypass harnesses. I'm also assuming that if it is a vats problem, its at the fuel enable circuit. I know I'm doing a lot of assuming here and would not be hurt to be corrected. I have searched this forum for this but most posts deal with non cranking issues and the rest I find dont help to much. Thanks for any input and suggestions
Went for a short drive yesterday, was running well until engine just shut off and would not restart. Had it flatbedded home and started diagnosing today. Security light goes out as it should with switch on and I get no SYS light.Chck engine light not on.I have spark and fuel to rail (came out the schrader valve). Used a jumper to get the codes and it has code 46.I followed the troubleshooting in the FSM. I cant find a open or short in ckt 229, so went on to check the ccm. It has no codes,which I thought would have a code 54...fuel enable failure. At this point I am stuck. Is there any way to make sure of why this will not start, before I have to replace the ccm, which is what the FSM says is next? I'm assuming that if the engine will turn over then its not a bad key or ignition problem that I could bypass with the available bypass harnesses. I'm also assuming that if it is a vats problem, its at the fuel enable circuit. I know I'm doing a lot of assuming here and would not be hurt to be corrected. I have searched this forum for this but most posts deal with non cranking issues and the rest I find dont help to much. Thanks for any input and suggestions
Thread Starter
Advanced
Joined: Feb 2007
Posts: 54
Likes: 0
From: Woodville Alabama
If you can give a brief explanation how to do this I will do tomorrow. Can you tell me if I seem to have power to the injectors by my follow up post. Should the test light be blinking on and off when cranking the engine? Would bad injectors cause the engine to go completely dead at a cruising speed and make it impossible to restart?
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
If you can give a brief explanation how to do this I will do tomorrow. Can you tell me if I seem to have power to the injectors by my follow up post. Should the test light be blinking on and off when cranking the engine? Would bad injectors cause the engine to go completely dead at a cruising speed and make it impossible to restart?
Thread Starter
Advanced
Joined: Feb 2007
Posts: 54
Likes: 0
From: Woodville Alabama
OK I will do this tomorrow after work and post my results. I hope it is something as simple as this as injectors were next on my list to replaced anyway. This would just move up the schedule a bit. Let me ask this though...by the way I understand the FSM, the injector connectors have voltage all the time(with switch on and to make them "fire" the circuit goes to ground,hence a test light would "blink" when the engine is turned over. Mine is not doing this, making me think that the ccm has the fuel "disabled". Thanks for your reply and help!
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
OK I will do this tomorrow after work and post my results. I hope it is something as simple as this as injectors were next on my list to replaced anyway. This would just move up the schedule a bit. Let me ask this though...by the way I understand the FSM, the injector connectors have voltage all the time(with switch on and to make them "fire" the circuit goes to ground,hence a test light would "blink" when the engine is turned over. Mine is not doing this, making me think that the ccm has the fuel "disabled". Thanks for your reply and help!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Advanced
Joined: Feb 2007
Posts: 54
Likes: 0
From: Woodville Alabama
i don't exactly know what happens to the CCM when it sences voltage going back through the ECU via the injector ground. I can't find anyone that has ever even toyed with the idea. All i know is many people change the CCM to no avail. Dealers change them all the time, and still same problem untill the bad injector is taken out. Will this be your problem, I hope so.
Injector readings#1-16.5,#3-16.6,#5-16.5,#7-16.6,#2 -16.7, #4-16.4,#6-16.7,#8-16.4
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
Safety Car
Joined: Oct 2007
Posts: 3,816
Likes: 0
From: :45 minutes from everywhere / E-I-E-I-O
OK I will do this tomorrow after work and post my results. I hope it is something as simple as this as injectors were next on my list to replaced anyway. This would just move up the schedule a bit. Let me ask this though...by the way I understand the FSM, the injector connectors have voltage all the time(with switch on and to make them "fire" the circuit goes to ground,hence a test light would "blink" when the engine is turned over. Mine is not doing this, making me think that the ccm has the fuel "disabled". Thanks for your reply and help!
)Check your '90 FSM to see if ig control circuit problems will disable injectors.
Thread Starter
Advanced
Joined: Feb 2007
Posts: 54
Likes: 0
From: Woodville Alabama
There is a condition that will disable injectors (on a '94 anyway), so that the engine does not flood. DTC41 open ig control circuit, which I'm workin' on now... (workin' on me is more like it )
Check your '90 FSM to see if ig control circuit problems will disable injectors.
)Check your '90 FSM to see if ig control circuit problems will disable injectors.
