ALDL Fault Codes - ZR-1 Net Registry Forums

Dynomite · 09-30-2015

Assembly Line Diagnostic Link (ALDL) Fault Codes

1. ZR1 ECM CODES 1990 TO 1992
Code #12: Normal No Codes.
Code #13: Left Oxygen Sensor Circuit.
Code #14: Coolant Temperature Sensor Circuit High.
Code #15: Coolant Temperature Sensor Circuit Low.
Code #16: Direct Ignition System (DIS) Fault Line Circuit
Code #21: Throttle Position Sensor Circuit High.
Code #22: Throttle Position Sensor Circuit Low.
Code #23: Manifold Air Temperature Sensor Circuit Low.
Code #24: Vehicle Speed Sensor Circuit.
Code #25: Manifold Air Temperature Sensor Circuit High.
Code #31: Camshaft Sensor Circuit.
Code #33: Manifold Absolute Pressure Sensor Circuit High - Low Vacuum.
Code #34: Manifold Absolute Pressure Sensor Circuit Low - High Vacuum.
Code #36: Direct Ignition System (DIS) Circuit (missing or extra EST signal)
Code #41: Cylinder Select Error (Faulty or Incorrect Mem-Cal)
Code #42: Electronic Spark Timing (EST) Circuit.
Code# 43: Electronic Spark Control (ESC) Circuit.
Code #44: Left Oxygen Sensor Circuit Lean.
Code #45: Left Oxygen Sensor Circuit Rich.
Code #46: Vehicle Anti-Theft System (VATS)(PASS-Key) Circuit.
Code #51: Mem-Cal Error.
Code #52: Engine Oil Temperature Sensor Circuit Low.
Code #53: System Voltage.
Code #54: Fuel Pump Circuit (Low Voltage)
Code #55: System Voltage
Code #56: Vacuum Sensor Circuit.
Code #61: Secondary Port Throttle Valve System.
Code #62: Engine Oil Temperature Sensor Circuit High.
Code #63: Right Oxygen Sensor Circuit Open.
Code #64: Right Oxygen Sensor Circuit Lean.
Code #65: Right Oxygen Sensor Circuit Rich
Code #66: Power fault for the valet switch.

2. ECM Related Explanations.
31 LCD Data Circuit-Circuit shorted to battery voltage or CCM driver open
33 Data Clock Circuit-Circuit shorted to battery voltage or CCM driver open
35 Data Strobe Circuit-Circuit shorted to battery voltage or CCM driver open
37 M Clock Circuit-Circuit shorted to battery voltage or CCM driver open
72 LCD Dimming Open Circuit-Circuit open or shorted to ground (radio & Climate control)
H History code. May be intermittant.
Code 31, 33, 35 related to the circuit from the CCM to the Instrument panel LCD.
CCM 74 is also a lighting circuit problem.
CCM 41 is loss of communication with the ECM.

3. ZR1 ABS Code - Definition
1990 Service Manual:
(* = Requires Tech 1 Daignostic Tool)
12 - Diagnostic System Operational
21 - RF Wheel Speed Sensor Fault
22 - RF Toothed Wheel Frequency Error
25 - LF Wheel Speed Sensor Fault
26 - LF Toothed Wheel Frequency Error
31 - RR Wheel Speed Sensor Fault
32 - RR Toothed Wheel Frequency Error
35 - LR Wheel Speed Sensor Fault
36 - LR Toothed Wheel Frequency Error
41* - RF Solenoid Valve Fault
45* - LF Solenoid Valve Fault
55* - Rear Solenoid Valve Fault
61* - Pump Motor or Motor Relay Fault
63* - Solenoid Valve Relay Fault
71 - EBCM Fault
72 - Serial Data Link Fault
75 - Lateral Accelerometer Fault (Short to B+ or Ground, or Open Circuit)
76 - Lateral Accelerometer Fault (Signal Out of Range or Incorrect)
Clearing Codes
The fault codes in the EBCM's memory are erased in one of three ways:
1. Diagnostic Enable Line Procedure
2. Tech 1 "Clear Codes" Selection
3. Igniton Cycle Default
Whichever method is used, be sure to verify proper system operation and absence of codes when clearing procedure is completed.

4. ZR1 Ride Control (SRC) Codes.
12 = Start of sequence
13 = Left rear time out
14 = Right Front time out
21 = Left Front time out
22 = Right Rear time out
31 = Left Front out of position
32 = Right Front out of position
33 = Left Rear out of position
34 = Right Rear out of position
Out of position codes are triggered if the computer senses that the actuator has not found the end stop position on the shock. Remove actuator at the indicated shock. Turn the valve gear on the shock stops after about 3 / 4 of turn, then you have a bad actuator. If it spins around continuously then it is a bad shock
41 = Selective ride control switch short to voltage
42 = Selective ride control switch open contacts
You can have a code 42 if you leave the switch in between indented positions
43 = selective ride control switch circuit open.
23 = If you start the car more than 3 times and do not move the car this code will set. Drive 3-6 feet and the light will go out.
The ride control controller is located in the bin behind the drivers seat mounted with the ABS controller.

5. ZR-1 CCM Codes
Code Definition
1.1 DISPLAY CCM fault codes
12 On-board diagnostics no codes (this is a good thing: no problem found)
13 DIC switches open or shorted to battery
14 DIC switches shorted to ground
16 Ignition 3 fuse circuit open
21 Horn relay coil shorted to battery or CCM internal open circuit
22 Rear defogger relay coil shorted to battery or CCM internal open circuit
24 Courtesy lamp relay coil shorted to battery or CCM internal open circuit
25 Courtesy lamp relay coil circuit open or shorted to ground
26 LCD blanking control circuit shorted to battery or CCM internal open
27 LCD blanking control circuit open or shorted to ground
31 LCD data circuit shorted to battery or CCM internal open
32 LCD data circuit open or shorted to ground
33 Data clock circuit shorted to battery or CCM internal open circuit
34 Data clock circuit open or shorted to ground
35 Data strobe circuit shorted to battery or CCM internal open circuit
36 Data strobe circuit open or shorted to ground
37 M clock circuit shorted to battery or CCM internal open circuit
38 M clock circuit open or shorted to ground
41 Loss of ECM serial data communications
51 Pass-key invalid key detection
52 Pass-key key detection circuit shorted
53 Pass-key ? key detection circuit open or shorted to battery
54 FEDS fuel enable failure
61 Pass-key ? key #1 programming resistance out of range
62 Pass-key ? key #2 programming resistance out of range
63 Pass-key ? key #2 programming resistance low
71 LCD dimming output circuit shorted to battery or CCM internal open circuit
72 LCD dimming output circuit open or shorted to ground
73 LED display dimming output circuit shorted to battery or CCM internal open circuit
74 LED display dimming output circuit open or shorted to ground

6. 1990 SIR Codes
For 90-93 Cars jumper A to K on the ALDL and the INFL REST light will flash
1990 SIR Codes
14 Front Sensor #1 (LH); Short to Ground
15 Front Sensor #1 (LH); Open Circuit
16 Front Sensor #1 (LH); Sensor Fault
24 Front Sensor #1 (RH); Short to Ground
25 Front Sensor #1 (RH); Open Circuit
26 Front Sensor #1 (RH); Sensor Fault
31 Inflator Squib; Current leakage to Battery
32 Inflator Squib; Current shorted to battery voltage
33 Inflator Squib; Current leakage to ground
34 Inflator Squib; Current shorted to ground
35 Inflator Squib; Open circuit
36 Inflator Squib; Squib fault
41 Indicator lamp circuit; Shorted to battery or ground
42 Indicator lamp circuit; Open circuit
51 Diagnostic unit faulty
52 Firing sequence confirmation set
53 Firing current confirmation set
54 Squib current has flowed

7. 91 & 92 & 93 SIR Codes
21 Steering Column Resistance Too High
22 Steering Column Resistance Too Low
23 Steering Column Circuit Voltage Too High
24 Steering Column Circuit Voltage Too Low
25 Short to Battery in Steering Column
26 Open in Steering Column Circuit
31 Open 36 VLR to Deployment Loop
32 Grounded 36 VLR to Deployment Loop
33 Diode B Shorted in Wiring Harness
34 Open in Ignition 1 Feed to Deployment Loop
35 Discriminating Sensor Open
41 Deployment Loop Energy Reserve Voltage Fault
42 Deployment Loop Energy Reserve Voltage Fault
51 Accident Detected
52 EEPROM Accident Data Area Full
61 Force Low or â??INFL RESTâ? Warning Lamp Circuit
71 Internal DERM Fault

8. 94 & 95 SIR Codes
For 94-95 Cars, jumper Terminal 4 to 12 on the ALDL and enter the CCM diagnostics, or use a Tech1
14 Dual Pole Arming Sensor Disconnected
15 Passenger Initiator Circuit Resistance High
16 Passenger Initiator Circuit Resistance Low
17 Passenger Initiator Circuit Open
18 Discriminating Sensor Interconnect Open
19 Passenger Initiator Circuit Voltage High
21 Driver Initiator Circuit Resistance High
22 Driver Initiator Circuit Resistance Low
23 Driver Initiator Circuit Voltage High
24 Driver Initiator Circuit Voltage Low
25 Initiator Circuit Short to Ignition
26 Driver Initiator Circuit Open
28 Current Sink or Source Failure
31 Driver Loop Energy Reserve Feed Open
34 Dual Pole Arming Sensor Ignition Feed Open
35 Discriminating Sensor Open or Missing
36 Passenger Loop Energy Feed Open
42 Loop Energy Reserve Volatage Low
43 Driver Source Feed Low
44 Passenger Source Feed Low
51 Frontal Crash Detected
52 Data Area Full
53 Driver Side Low High Resistance
54 Passenger Side Low High Resistance
55 DERM Incompatibility
61 SIR Indicator Circuit Failure
62 Redundant Indicator Circuit Failure
71 and or 75 Internal DERM Fault
81 Driver Ignition Diode Open
82 Passenger Ignition Diode Open
83 Driver Reserve Diode Shorted
84 Passenger Reserve Diode Shorted

NOTE: SIR Code 13 will be displayed (In addition to Code 12) only if no history codes are in memory. To read history codes, a SCAN/TECH tool must be used.
Read more: The Seat Belt Question

09-30-2015	#1
Dynomite Join Date: Aug 2009 Location: South Dakota/California Posts: 3,788	ALDL Fault Codes Assembly Line Diagnostic Link (ALDL) Fault Codes 1. ZR1 ECM CODES 1990 TO 1992 Code #12: Normal No Codes. Code #13: Left Oxygen Sensor Circuit. Code #14: Coolant Temperature Sensor Circuit High. Code #15: Coolant Temperature Sensor Circuit Low. Code #16: Direct Ignition System (DIS) Fault Line Circuit Code #21: Throttle Position Sensor Circuit High. Code #22: Throttle Position Sensor Circuit Low. Code #23: Manifold Air Temperature Sensor Circuit Low. Code #24: Vehicle Speed Sensor Circuit. Code #25: Manifold Air Temperature Sensor Circuit High. Code #31: Camshaft Sensor Circuit. Code #33: Manifold Absolute Pressure Sensor Circuit High - Low Vacuum. Code #34: Manifold Absolute Pressure Sensor Circuit Low - High Vacuum. Code #36: Direct Ignition System (DIS) Circuit (missing or extra EST signal) Code #41: Cylinder Select Error (Faulty or Incorrect Mem-Cal) Code #42: Electronic Spark Timing (EST) Circuit. Code# 43: Electronic Spark Control (ESC) Circuit. Code #44: Left Oxygen Sensor Circuit Lean. Code #45: Left Oxygen Sensor Circuit Rich. Code #46: Vehicle Anti-Theft System (VATS)(PASS-Key) Circuit. Code #51: Mem-Cal Error. Code #52: Engine Oil Temperature Sensor Circuit Low. Code #53: System Voltage. Code #54: Fuel Pump Circuit (Low Voltage) Code #55: System Voltage Code #56: Vacuum Sensor Circuit. Code #61: Secondary Port Throttle Valve System. Code #62: Engine Oil Temperature Sensor Circuit High. Code #63: Right Oxygen Sensor Circuit Open. Code #64: Right Oxygen Sensor Circuit Lean. Code #65: Right Oxygen Sensor Circuit Rich Code #66: Power fault for the valet switch. 2. ECM Related Explanations. 31 LCD Data Circuit-Circuit shorted to battery voltage or CCM driver open 33 Data Clock Circuit-Circuit shorted to battery voltage or CCM driver open 35 Data Strobe Circuit-Circuit shorted to battery voltage or CCM driver open 37 M Clock Circuit-Circuit shorted to battery voltage or CCM driver open 72 LCD Dimming Open Circuit-Circuit open or shorted to ground (radio & Climate control) H History code. May be intermittant. Code 31, 33, 35 related to the circuit from the CCM to the Instrument panel LCD. CCM 74 is also a lighting circuit problem. CCM 41 is loss of communication with the ECM. 3. ZR1 ABS Code - Definition 1990 Service Manual: (* = Requires Tech 1 Daignostic Tool) 12 - Diagnostic System Operational 21 - RF Wheel Speed Sensor Fault 22 - RF Toothed Wheel Frequency Error 25 - LF Wheel Speed Sensor Fault 26 - LF Toothed Wheel Frequency Error 31 - RR Wheel Speed Sensor Fault 32 - RR Toothed Wheel Frequency Error 35 - LR Wheel Speed Sensor Fault 36 - LR Toothed Wheel Frequency Error 41* - RF Solenoid Valve Fault 45* - LF Solenoid Valve Fault 55* - Rear Solenoid Valve Fault 61* - Pump Motor or Motor Relay Fault 63* - Solenoid Valve Relay Fault 71 - EBCM Fault 72 - Serial Data Link Fault 75 - Lateral Accelerometer Fault (Short to B+ or Ground, or Open Circuit) 76 - Lateral Accelerometer Fault (Signal Out of Range or Incorrect) Clearing Codes The fault codes in the EBCM's memory are erased in one of three ways: 1. Diagnostic Enable Line Procedure 2. Tech 1 "Clear Codes" Selection 3. Igniton Cycle Default Whichever method is used, be sure to verify proper system operation and absence of codes when clearing procedure is completed. 4. ZR1 Ride Control (SRC) Codes. 12 = Start of sequence 13 = Left rear time out 14 = Right Front time out 21 = Left Front time out 22 = Right Rear time out 31 = Left Front out of position 32 = Right Front out of position 33 = Left Rear out of position 34 = Right Rear out of position Out of position codes are triggered if the computer senses that the actuator has not found the end stop position on the shock. Remove actuator at the indicated shock. Turn the valve gear on the shock stops after about 3 / 4 of turn, then you have a bad actuator. If it spins around continuously then it is a bad shock 41 = Selective ride control switch short to voltage 42 = Selective ride control switch open contacts You can have a code 42 if you leave the switch in between indented positions 43 = selective ride control switch circuit open. 23 = If you start the car more than 3 times and do not move the car this code will set. Drive 3-6 feet and the light will go out. The ride control controller is located in the bin behind the drivers seat mounted with the ABS controller. 5. ZR-1 CCM Codes Code Definition 1.1 DISPLAY CCM fault codes 12 On-board diagnostics no codes (this is a good thing: no problem found) 13 DIC switches open or shorted to battery 14 DIC switches shorted to ground 16 Ignition 3 fuse circuit open 21 Horn relay coil shorted to battery or CCM internal open circuit 22 Rear defogger relay coil shorted to battery or CCM internal open circuit 24 Courtesy lamp relay coil shorted to battery or CCM internal open circuit 25 Courtesy lamp relay coil circuit open or shorted to ground 26 LCD blanking control circuit shorted to battery or CCM internal open 27 LCD blanking control circuit open or shorted to ground 31 LCD data circuit shorted to battery or CCM internal open 32 LCD data circuit open or shorted to ground 33 Data clock circuit shorted to battery or CCM internal open circuit 34 Data clock circuit open or shorted to ground 35 Data strobe circuit shorted to battery or CCM internal open circuit 36 Data strobe circuit open or shorted to ground 37 M clock circuit shorted to battery or CCM internal open circuit 38 M clock circuit open or shorted to ground 41 Loss of ECM serial data communications 51 Pass-key invalid key detection 52 Pass-key key detection circuit shorted 53 Pass-key ? key detection circuit open or shorted to battery 54 FEDS fuel enable failure 61 Pass-key ? key #1 programming resistance out of range 62 Pass-key ? key #2 programming resistance out of range 63 Pass-key ? key #2 programming resistance low 71 LCD dimming output circuit shorted to battery or CCM internal open circuit 72 LCD dimming output circuit open or shorted to ground 73 LED display dimming output circuit shorted to battery or CCM internal open circuit 74 LED display dimming output circuit open or shorted to ground 6. 1990 SIR Codes For 90-93 Cars jumper A to K on the ALDL and the INFL REST light will flash 1990 SIR Codes 14 Front Sensor #1 (LH); Short to Ground 15 Front Sensor #1 (LH); Open Circuit 16 Front Sensor #1 (LH); Sensor Fault 24 Front Sensor #1 (RH); Short to Ground 25 Front Sensor #1 (RH); Open Circuit 26 Front Sensor #1 (RH); Sensor Fault 31 Inflator Squib; Current leakage to Battery 32 Inflator Squib; Current shorted to battery voltage 33 Inflator Squib; Current leakage to ground 34 Inflator Squib; Current shorted to ground 35 Inflator Squib; Open circuit 36 Inflator Squib; Squib fault 41 Indicator lamp circuit; Shorted to battery or ground 42 Indicator lamp circuit; Open circuit 51 Diagnostic unit faulty 52 Firing sequence confirmation set 53 Firing current confirmation set 54 Squib current has flowed 7. 91 & 92 & 93 SIR Codes 21 Steering Column Resistance Too High 22 Steering Column Resistance Too Low 23 Steering Column Circuit Voltage Too High 24 Steering Column Circuit Voltage Too Low 25 Short to Battery in Steering Column 26 Open in Steering Column Circuit 31 Open 36 VLR to Deployment Loop 32 Grounded 36 VLR to Deployment Loop 33 Diode B Shorted in Wiring Harness 34 Open in Ignition 1 Feed to Deployment Loop 35 Discriminating Sensor Open 41 Deployment Loop Energy Reserve Voltage Fault 42 Deployment Loop Energy Reserve Voltage Fault 51 Accident Detected 52 EEPROM Accident Data Area Full 61 Force Low or â??INFL RESTâ? Warning Lamp Circuit 71 Internal DERM Fault 8. 94 & 95 SIR Codes For 94-95 Cars, jumper Terminal 4 to 12 on the ALDL and enter the CCM diagnostics, or use a Tech1 14 Dual Pole Arming Sensor Disconnected 15 Passenger Initiator Circuit Resistance High 16 Passenger Initiator Circuit Resistance Low 17 Passenger Initiator Circuit Open 18 Discriminating Sensor Interconnect Open 19 Passenger Initiator Circuit Voltage High 21 Driver Initiator Circuit Resistance High 22 Driver Initiator Circuit Resistance Low 23 Driver Initiator Circuit Voltage High 24 Driver Initiator Circuit Voltage Low 25 Initiator Circuit Short to Ignition 26 Driver Initiator Circuit Open 28 Current Sink or Source Failure 31 Driver Loop Energy Reserve Feed Open 34 Dual Pole Arming Sensor Ignition Feed Open 35 Discriminating Sensor Open or Missing 36 Passenger Loop Energy Feed Open 42 Loop Energy Reserve Volatage Low 43 Driver Source Feed Low 44 Passenger Source Feed Low 51 Frontal Crash Detected 52 Data Area Full 53 Driver Side Low High Resistance 54 Passenger Side Low High Resistance 55 DERM Incompatibility 61 SIR Indicator Circuit Failure 62 Redundant Indicator Circuit Failure 71 and or 75 Internal DERM Fault 81 Driver Ignition Diode Open 82 Passenger Ignition Diode Open 83 Driver Reserve Diode Shorted 84 Passenger Reserve Diode Shorted NOTE: SIR Code 13 will be displayed (In addition to Code 12) only if no history codes are in memory. To read history codes, a SCAN/TECH tool must be used. Read more: The Seat Belt Question __________________ Left Clickable links -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 10-06-2016 at 02:29 PM.