Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

5.7L V8 VIN R Auto

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5.7L V8 VIN R Auto

Trouble Code: P0157



HO2S-22 (Bank 2 Sensor 2) Circuit Low Input

Possible Causes:



Air leaks in the exhaust system, intake manifold, vacuum lines
 
Engine misfire condition present (look for P0300 series codes)
 
Fuel system too lean (possible low fuel pressure, water in fuel)
 
HO2S signal circuit is shorted to the sensor or chassis ground
 
HO2S is damaged (i.e., cracked) or air reference hole clogged
 
PCM has failed
 

Trouble Code: P0158



HO2S-22 (Bank 2 Sensor 2) Circuit High Input

Possible Causes:



Fuel system rich (high fuel pressure, fuel pressure regulator leaking, or injector sticking)
 
HO2S element is silicon, water or fuel contaminated
 
HO2S signal circuit is shorted to system power (B+)
 
HO2S signal tracking (water intrusion) in the connector causing a short between the HO2S signal and heater power circuits
 
PCM has failed
 

Trouble Code: P0160



HO2S-22 (Bank 2 Sensor 2) Insufficient Activity

Possible Causes:



Exhaust leak present in the exhaust manifold or exhaust pipes
 
HO2S signal or ground circuit has a high resistance condition
 
HO2S element is silicon, water or fuel contaminated
 

Trouble Code: P0161



HO2S-22 (Bank 2 Sensor 2) Heater Circuit Malfunction

Possible Causes:



HO2S heater ground circuit is open or has high resistance
 
HO2S heater power circuit is open (test O2S fuse in fuse block)
 
HO2S heater element is damaged or has failed
 
PCM has failed
 
TSB 00-06-04-006 contains a repair procedure for this code
 

Trouble Code: P0401



Insufficient EGR Flow Detected

Possible Causes:



Base engine problem (e.g., a severely restricted exhaust)
 
EGR vacuum hoses damaged, loose or routed incorrectly
 
EGR passages or intake passages clogged or restricted
 
EGR solenoid valve is clogged (carbon), damaged or has failed
 

Trouble Code: P0462



Fuel Level Sensor Low Input

Possible Causes:



Fuel level sensor signal circuit is shorted to ground between the fuel level sensor and the PCM connector
 
Fuel level sender is damaged, binding or not aligned properly
 
PCM has failed
 

Trouble Code: P0463



Fuel Level Sensor High Input

Possible Causes:



Fuel level sensor signal circuit is shorted to system power
 
Fuel level sensor ground circuit is open
 
Fuel level sender is damaged, binding or not aligned properly
 
PCM has failed
 

Trouble Code: P0502



VSS Circuit Low Input (4L60-E, 4L80-E)

Possible Causes:



Output shaft rotor is chipped or damaged
 
OSS tip contains debris or metal shavings (an intermittent fault)
 
OSS positive (+) signal circuit is open or shorted to ground
 
OSS negative (-) signal circuit is open or shorted to ground
 
OSS is damaged or has failed (an intermittent fault)
 

Trouble Code: P0503



Title: VSS Circuit Malfunction (4L60-E, 4L80-E)

Possible Causes:



Output shaft rotor is chipped or damaged (intermittent fault)
 
OSS tip contains debris or metal shavings (an intermittent fault)
 
OSS (+) signal circuit is open or shorted to ground (intermittent)
 
OSS (-) signal circuit is open or shorted to ground (intermittent)
 
OSS is damaged or has failed (an intermittent fault)
 

Trouble Code: P0601



Control Module ROM Malfunction

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 
TSB 67-65-23 contains a repair procedure for this code
 

Trouble Code: P0602



Control Module Not Programmed

Possible Causes:



Reprogram the PCM with the correct software and calibration. If this step does not correct the problem, the PCM must be replaced and programmed with the correct software/calibration.
 

Trouble Code: P0603



Control Module Long Term Memory Reset

Possible Causes:



An interruption to the PCM main power and/or ground circuits
 
Check the PCM power and ground circuits and make repairs as necessary. Clear the codes and recheck. If it resets, the PCM must be replaced and programmed with the correct software.
 

Trouble Code: P0604



Control Module Random Access Memory Failure

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 

Trouble Code: P0606



Control Module Internal Performance

Possible Causes:



The PCM must be replaced to correct this problem. A new PCM must be programmed with the correct software/calibration.
 

Trouble Code: P1336



CKP Sensor System Variation Not Learned

Possible Causes:



Set the parking brake and block the drive wheels for safety.
 
Verify the hood is closed.
 
Read the trouble codes. If a code is set, refer to that code.
 
Start the engine. Allow engine temperature to reach at least 158ºF (70ºC). Then key off.
 
Select Crankshaft Position Variation Learn procedure on Scan Tool & start the vehicle.
 
Apply the brake pedal firmly and verify the selector is in Park.
 
Increase accelerator pedal position until fuel cutoff is reached at the test rpm (e.g., 5150). Quickly release the accelerator pedal after fuel cutoff is reached. The CKP system variation compensating values are learned when the engine speed (rpm) decreases back to idle speed and the procedure terminates.
 
Read the trouble codes and recheck for DTC P1336.
 
If DTC P1336 runs and passes, the CKP system variation "learn" procedure is complete. If not, look for other codes. If no codes are set, repeat the test procedure.
 

Trouble Code: U1000



Class 2 Communication Malfunction

Possible Causes:



Class 2 circuit is open, shorted to ground or shorted to power
 
PCM ignition power circuit(s) has a high resistance condition
 
PCM main ground circuit(s) has a high resistance condition
 
SDM (module) could be shorted pulling the voltage low
 

Trouble Code: U1016



No Communication With Powertrain Control Module

Possible Causes:



PCM Class 2 circuit is open, shorted to ground or to B+
 
PCM ignition power circuit(s) has a high resistance condition
 
PCM main ground circuit(s) has a high resistance condition
 
PCM (module) may have failed and is pulling the circuit low
 

Trouble Code: U1026



Loss of ATC Class 2 Communication

Possible Causes:



Check for a loose connection at the ATC module
 
Test the main power and ground circuits to the ATC module
 
Check the Class 2 serial data circuit to the ATC module
 
ATC module may have failed
 

Trouble Code: U1041



Loss of Electronic Brake Controller Communication

Possible Causes:



Check for a loose connection at the EBCM (module)
 
Test the main power and ground circuits to the EBCM (module)
 
Check the Class 2 serial data circuit to the EBCM (module)
 
EBCM (module) may have failed
 

Trouble Code: U1048



No Communication With Rear Wheel Steering Control Module

Possible Causes:



RWSCM Class 2 circuit is open, shorted to ground or to B+
 
RWSCM ignition power circuit has a high resistance condition
 
RESCM main ground circuit(s) has a high resistance condition
 
RESCM (module) may have failed and is pulling the circuit low
 

Trouble Code: U1064



No Communication With Body Control Module

Possible Causes:



BCM Class 2 circuit is open, shorted to ground or to B+
 
BCM ignition power circuit has a high resistance condition
 
BCM main ground circuit(s) has a high resistance condition
 
BCM (module) may have failed and is pulling the circuit low
 

Trouble Code: U1088



No Communication With SDM (Restraint Module)

Possible Causes:



SDM Class 2 circuit is open, shorted to ground or to B+
 
SDM ignition power circuit has a high resistance condition
 
SDM main ground circuit(s) has a high resistance condition
 
SDM (module) may have failed and is pulling the circuit low
 

Trouble Code: U1096



No Communication With Instrument Panel Cluster

Possible Causes:



IPC Class 2 circuit is open, shorted to ground or to B+
 
IPC ignition power circuit has a high resistance condition
 
IPC main ground circuit(s) has a high resistance condition
 
IPC (module) may have failed and is pulling the circuit low
 

Trouble Code: U1097



No Communication With Driver Information Center

Possible Causes:



DIC Class 2 circuit is open, shorted to ground or to B+
 
DIC ignition power circuit has a high resistance condition
 
DIC main ground circuit(s) has a high resistance condition
 
DIC (module) may have failed and is pulling the circuit low
 

Trouble Code: U1151



No Communication With Vehicle Interface Unit

Possible Causes:



VIU Class 2 circuit is open, shorted to ground or to B+
 
VIU ignition power circuit has a high resistance condition
 
VIU main ground circuit(s) has a high resistance condition
 
VIU (module) may have failed and is pulling the circuit low
 

Trouble Code: U1152



No Communication With HVAC Control Module

Possible Causes:



HVAC Class 2 circuit is open, shorted to ground or to B+
 
HVAC ignition power circuit has a high resistance condition
 
HVAC main ground circuit(s) has a high resistance condition
 
HVAC (module) may have failed and is pulling the circuit low
 

Trouble Code: U1193



Loss of Vehicle Immobilizer Module Communications

Possible Causes:



Test the main power and ground circuits to the VIM module for a loose connection
 
Check the Class 2 serial data circuit to the VIM module
 
VTD module may have failed
 

Trouble Code: U1255



Class 2 Communications Malfunction

Possible Causes:



Class 2 circuit is open, shorted to ground or shorted to power
 
PCM ignition power circuit(s) has a high resistance condition
 
PCM main ground circuit(s) has a high resistance condition
 

Trouble Code: U1305



Class 2 Data Link High or Low

Possible Causes:



Class 2 serial data line has either a high or low voltage condition on the circuit, and the module cannot identify the fault
 
One or more modules on Class 2 line has an short to power
 
One or more modules on the Class 2 line has a short to ground
 

 
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