trouble codes not working
Thread Starter
Joined: Jul 2002
Posts: 2,789
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From: NOR CAL USA
Car: 89 iroc-z 5.7tpi 350,
Engine: 5.7tpi 350,
Transmission: T-56
trouble codes not working
when i put the pin in the port under the dash to get the codes, when i turn the ignition key, it just keeps blinking one solid pattern. not the codes its supposed to produce. what causes this? i just picked up this car and this is the first time trying to diagnose a chek engine light i had recieved. the ecm in the car is new (about 3 months old) would this have anything to do with it?
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Joined: Apr 2000
Posts: 3,187
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From: E.B.F. TN
Car: Tree Huggers
Engine: Do Not
Transmission: Appreciate Me.
Some info I scabbed off some guy wearing a phallic symbol style metal can on his head. Gave off some evil vibes too (Believe me I know). EEEEvviilll....
Originally posted by Vader
Actually, the jumper (or any resistance below 500 ohms) can be inserted after the engine is running to invoke the Diagnostic / Field Service Mode. Attempting to start an engine while in Diagnostic Mode (diagnostic request terminal 'B' grounded, engine off) can damage the firmware (not always does, but can).
Diagnostic mode will will display malfunctions stored in nonvolatile memory and perform other functions as described below when the diagnostic display mode is enabled. This mode requires that the diagnostic request line be grounded and that the engine not be running (see EST).
Solenoid Energization
When the diagnostic display mode is enabled and the battery voltage is less than 16.9V, the diagnostic control logic will energize the AIR control, AIR select, TCC, EGR solenoid, A/C and EVAP canister purge solenoids. In addition, the idle air control motor will be continuously pulsed to retract while in diagnostic display mode.
The solenoid energization function is capable of operating without a calibration PROM installed in the ECM. The purpose of this function is to allow a means to force the ECM to energize its outputs for troubleshooting purposes, and to provide a means for exercising the ECM output devices during burn-in at the factory.
Malfunction Code Suppression
While the diagnostic display mode is enabled, the diagnostic control logic will force the diagnostic control counter to zero. This action has the effect of preventing new malfunctions from being logged into nonvolatile memory while the diagnostic display mode is enabled.
Malfunction Code Display
Each malfunction condition is associated with a two digit code number. When the diagnostic display mode is enabled, the diagnostic control logic will flash the check engine lamp in a logical sequence to depict the two digit code associated with each malfunction stored in nonvolatile memory.
Each code displayed will consist of a number of flashes representing the first digit followed by a short pause, followed by a number of flashes representing the second digit, followed by a long pause indicating the end of the code.
Each stored code is displayed three times before proceeding to the next code. After all malfunction codes stored in nonvolatile memory have been thus displayed, the entire flashing sequence is repeated.
Field Service Mode will display some basic ECM information via the SES lamp. If the ECM is in Open-Loop mode, the SES light will flash rapidly, about 2½ times per second. If it's in Closed-Loop mode, it will flash about once per second. When in Closed Loop mode, flashing less than once per second indicates the ECM is enriching the mixture above the 128 count base line. Flashing more than once per second indicates the ECM is leaning the mixture below the 128 base line.
Inserting a 3.9K ohm resistance in the diagnostic request pin to ground will invoke Factory Test Mode or Backup Fuel and Spark Mode ("Limp Home Mode"), which forces the ECM to use predetermined fuel calculations in the ECM PROM instead of the learned inputs in active RAM. Backup fuel is usually around 12:1 or richer from the factory. Tthe ECM will turn on the check engine lamp in this mode.
A 10K ohm resistance in the diagnostic terminal to ground will invoke the factory End of Line Test Mode, or ALDL Mode. When the assembly line diagnostic mode is detected, the fuel logic will bypass the closed loop time criteria. The fuel logic will enter closed loop mode as soon as the coolant temperature and oxygen sensor thresholds are met. There will be no reset of the integrator function. The IAC will use the calibration memory table value corresponding to a battery voltage of 8 volts, bypass certain criteria for RPM closed loop enable, and bypass coolant restrictions for enabling IAC kick-down mode. The EST system will disable the Burst Knock logic and bypass the RPM and coolant temperature criteria for ESC retard enable. That will force the engine into a condition where spark knock should occur if the throttle is suddenly opened (Burst Knock). Additionally, if ALDL mode has been enabled longer than a PROM timer value, the timer will be removed from the spark advance calculation. The TCC logic will allow the TCC to be enabled sooner and without regard to the CTS input.
Actually, the jumper (or any resistance below 500 ohms) can be inserted after the engine is running to invoke the Diagnostic / Field Service Mode. Attempting to start an engine while in Diagnostic Mode (diagnostic request terminal 'B' grounded, engine off) can damage the firmware (not always does, but can).
Diagnostic mode will will display malfunctions stored in nonvolatile memory and perform other functions as described below when the diagnostic display mode is enabled. This mode requires that the diagnostic request line be grounded and that the engine not be running (see EST).
Solenoid Energization
When the diagnostic display mode is enabled and the battery voltage is less than 16.9V, the diagnostic control logic will energize the AIR control, AIR select, TCC, EGR solenoid, A/C and EVAP canister purge solenoids. In addition, the idle air control motor will be continuously pulsed to retract while in diagnostic display mode.
The solenoid energization function is capable of operating without a calibration PROM installed in the ECM. The purpose of this function is to allow a means to force the ECM to energize its outputs for troubleshooting purposes, and to provide a means for exercising the ECM output devices during burn-in at the factory.
Malfunction Code Suppression
While the diagnostic display mode is enabled, the diagnostic control logic will force the diagnostic control counter to zero. This action has the effect of preventing new malfunctions from being logged into nonvolatile memory while the diagnostic display mode is enabled.
Malfunction Code Display
Each malfunction condition is associated with a two digit code number. When the diagnostic display mode is enabled, the diagnostic control logic will flash the check engine lamp in a logical sequence to depict the two digit code associated with each malfunction stored in nonvolatile memory.
Each code displayed will consist of a number of flashes representing the first digit followed by a short pause, followed by a number of flashes representing the second digit, followed by a long pause indicating the end of the code.
Each stored code is displayed three times before proceeding to the next code. After all malfunction codes stored in nonvolatile memory have been thus displayed, the entire flashing sequence is repeated.
Field Service Mode will display some basic ECM information via the SES lamp. If the ECM is in Open-Loop mode, the SES light will flash rapidly, about 2½ times per second. If it's in Closed-Loop mode, it will flash about once per second. When in Closed Loop mode, flashing less than once per second indicates the ECM is enriching the mixture above the 128 count base line. Flashing more than once per second indicates the ECM is leaning the mixture below the 128 base line.
Inserting a 3.9K ohm resistance in the diagnostic request pin to ground will invoke Factory Test Mode or Backup Fuel and Spark Mode ("Limp Home Mode"), which forces the ECM to use predetermined fuel calculations in the ECM PROM instead of the learned inputs in active RAM. Backup fuel is usually around 12:1 or richer from the factory. Tthe ECM will turn on the check engine lamp in this mode.
A 10K ohm resistance in the diagnostic terminal to ground will invoke the factory End of Line Test Mode, or ALDL Mode. When the assembly line diagnostic mode is detected, the fuel logic will bypass the closed loop time criteria. The fuel logic will enter closed loop mode as soon as the coolant temperature and oxygen sensor thresholds are met. There will be no reset of the integrator function. The IAC will use the calibration memory table value corresponding to a battery voltage of 8 volts, bypass certain criteria for RPM closed loop enable, and bypass coolant restrictions for enabling IAC kick-down mode. The EST system will disable the Burst Knock logic and bypass the RPM and coolant temperature criteria for ESC retard enable. That will force the engine into a condition where spark knock should occur if the throttle is suddenly opened (Burst Knock). Additionally, if ALDL mode has been enabled longer than a PROM timer value, the timer will be removed from the spark advance calculation. The TCC logic will allow the TCC to be enabled sooner and without regard to the CTS input.
Thread Starter
Joined: Jul 2002
Posts: 2,789
Likes: 0
From: NOR CAL USA
Car: 89 iroc-z 5.7tpi 350,
Engine: 5.7tpi 350,
Transmission: T-56
yes im grounding A and B.
it worked just fine in my RS, but this new iroc i have, i dunno its weird.
what you just posted in quotes made no sense to me. is thier a specific part that iw as supposed to catch onto?
it worked just fine in my RS, but this new iroc i have, i dunno its weird.
what you just posted in quotes made no sense to me. is thier a specific part that iw as supposed to catch onto?
Supreme Member
Joined: Apr 2000
Posts: 3,187
Likes: 0
From: E.B.F. TN
Car: Tree Huggers
Engine: Do Not
Transmission: Appreciate Me.
Is this in the '89 in your tagline or another year car? If so, what year?
If it's the '89 you might want to check the wires in the back of the ALDL. And also makes sure that the 'check engine light' comes on when you start the car (to verify that the bulb is not burned out).
If it's the '89 you might want to check the wires in the back of the ALDL. And also makes sure that the 'check engine light' comes on when you start the car (to verify that the bulb is not burned out).
Supreme Member
Joined: Jan 2002
Posts: 1,322
Likes: 1
From: Bloomingdale,IL
Car: 91 RS
Engine: 305 Tbi (L03)
Transmission: 700r4
When the diagnostic display mode is enabled and the battery voltage is less than 16.9V, the diagnostic control logic will energize the AIR control, AIR select, TCC, EGR solenoid, A/C and EVAP canister purge solenoids. In addition, the idle air control motor will be continuously pulsed to retract while in diagnostic display mode.
Senior Member
Joined: Aug 2001
Posts: 814
Likes: 2
From: San Jose, CA, USA
Car: 88 IROC-Z - original owner!
Engine: LB9 with K&Ns, MSD, Foil, Taylor
Transmission: WC T-5
Axle/Gears: BW 9-bolt, 3.45 posi
If you have shorted the pins on the ALDL and crazy things are happening, you could have a failed ECM.
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Joined: Sep 2003
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From: Woodland, CA
Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
ok this is TraviZ, i was on Porkyzilla's account cuz i was at his house when i posted.
anyways, the bulb is not burned out, it just flashes a steady pace, not the wannabe morse code BS. but anyways, their was a new ecm put in about 2-3 months ago, their has been no more trouble codes since i cleared it (battery) but i still am curious why it will jsut flash a steady pace.
anyways, the bulb is not burned out, it just flashes a steady pace, not the wannabe morse code BS. but anyways, their was a new ecm put in about 2-3 months ago, their has been no more trouble codes since i cleared it (battery) but i still am curious why it will jsut flash a steady pace.
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